1581621432 has 16 divisors (see below), whose sum is σ = 3954053640. Its totient is φ = 527207136.

The previous prime is 1581621407. The next prime is 1581621443. The reversal of 1581621432 is 2341261851.

It is a junction number, because it is equal to n+sod(n) for n = 1581621393 and 1581621402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32950423 + ... + 32950470.

Almost surely, 2^1581621432 is an apocalyptic number.

1581621432 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1581621432 is an abundant number, since it is smaller than the sum of its proper divisors (2372432208).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1581621432 is a wasteful number, since it uses less digits than its factorization.

1581621432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65900902 (or 65900898 counting only the distinct ones).

The product of its digits is 11520, while the sum is 33.

The square root of 1581621432 is about 39769.6043731893. The cubic root of 1581621432 is about 1165.1115667375. Note that the first 3 decimals are identical.

The spelling of 1581621432 in words is "one billion, five hundred eighty-one million, six hundred twenty-one thousand, four hundred thirty-two".