81911204 has 24 divisors (see below), whose sum is σ = 152009760. Its totient is φ = 38511936.

The previous prime is 81911201. The next prime is 81911213. The reversal of 81911204 is 40211918.

It is not an unprimeable number, because it can be changed into a prime (81911201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6479 + ... + 14345.

It is an arithmetic number, because the mean of its divisors is an integer number (6333740).

Almost surely, 2^81911204 is an apocalyptic number.

It is an amenable number.

81911204 is a deficient number, since it is larger than the sum of its proper divisors (70098556).

81911204 is a wasteful number, since it uses less digits than its factorization.

81911204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8027 (or 8025 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 81911204 is about 9050.4808712024. The cubic root of 81911204 is about 434.2912738167.

The spelling of 81911204 in words is "eighty-one million, nine hundred eleven thousand, two hundred four".