Each improvement assessment, with any penalty or interest incident to the nonpayment of the assessment, shall constitute a lien upon the lot or parcel of benefited property against which it is assessed. The lien shall attach to each lot or parcel of benefited property at the time the annual improvement assessment is made, and then shall take precedence over all other liens, whether created prior to or subsequent to the making of such improvement assessment, except state, county and municipal property taxes, and prior special assessments. The lien shall not be defeated or postponed by any private or judicial sale, by any mortgage, or by any error or mistake in the description of the property or in the names of the owners, if the description is sufficient to identify the property subject to the assessment. No irregularity in the proceedings of the governing body shall exempt any benefited property from the lien for the improvement assessment, or from the payment of the assessment, or from the penalties or interest on the assessment.