81776904 has 64 divisors (see below), whose sum is σ = 224562240. Its totient is φ = 24610560.

The previous prime is 81776899. The next prime is 81776911. The reversal of 81776904 is 40967718.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40462 + ... + 42434.

It is an arithmetic number, because the mean of its divisors is an integer number (3508785).

Almost surely, 2^81776904 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81776904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112281120).

81776904 is an abundant number, since it is smaller than the sum of its proper divisors (142785336).

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

81776904 is a wasteful number, since it uses less digits than its factorization.

81776904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2150 (or 2146 counting only the distinct ones).

The product of its (nonzero) digits is 84672, while the sum is 42.

The square root of 81776904 is about 9043.0583322237. The cubic root of 81776904 is about 434.0537921673.

The spelling of 81776904 in words is "eighty-one million, seven hundred seventy-six thousand, nine hundred four".