81900412 has 24 divisors (see below), whose sum is σ = 164586240. Its totient is φ = 35267760.

The previous prime is 81900409. The next prime is 81900439. The reversal of 81900412 is 21400918.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48148 + ... + 49819.

It is an arithmetic number, because the mean of its divisors is an integer number (6857760).

Almost surely, 2^81900412 is an apocalyptic number.

It is an amenable number.

81900412 is an abundant number, since it is smaller than the sum of its proper divisors (82685828).

81900412 is a wasteful number, since it uses less digits than its factorization.

81900412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98001 (or 97999 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 81900412 is about 9049.8846401487. The cubic root of 81900412 is about 434.2722000024.

The spelling of 81900412 in words is "eighty-one million, nine hundred thousand, four hundred twelve".