81925579008 has 864 divisors, whose sum is σ = 317088172800. Its totient is φ = 20641775616.

The previous prime is 81925578997. The next prime is 81925579037. The reversal of 81925579008 is 80097552918.

81925579008 is a `hidden beast` number, since 81 + 9 + 2 + 557 + 9 + 0 + 0 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 101267308 + ... + 101268116.

It is an arithmetic number, because the mean of its divisors is an integer number (367000200).

Almost surely, 2^81925579008 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 81925579008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158544086400).

81925579008 is an abundant number, since it is smaller than the sum of its proper divisors (235162593792).

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

81925579008 is a wasteful number, since it uses less digits than its factorization.

81925579008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 884 (or 857 counting only the distinct ones).

The product of its (nonzero) digits is 1814400, while the sum is 54.

The spelling of 81925579008 in words is "eighty-one billion, nine hundred twenty-five million, five hundred seventy-nine thousand, eight".