81908472940 has 48 divisors (see below), whose sum is σ = 206926675200. Its totient is φ = 26604856512.

The previous prime is 81908472923. The next prime is 81908472941. The reversal of 81908472940 is 4927480918.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81908472941) by changing a digit.

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, 15393670 + ... + 15398989.

It is an arithmetic number, because the mean of its divisors is an integer number (4310972400).

Almost surely, 2^81908472940 is an apocalyptic number.

It is an amenable number.

81908472940 is an abundant number, since it is smaller than the sum of its proper divisors (125018202260).

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

81908472940 is a wasteful number, since it uses less digits than its factorization.

81908472940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30792694 (or 30792692 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 52.

The spelling of 81908472940 in words is "eighty-one billion, nine hundred eight million, four hundred seventy-two thousand, nine hundred forty".