81292551620 has 24 divisors (see below), whose sum is σ = 195102124224. Its totient is φ = 27871731936.

The previous prime is 81292551577. The next prime is 81292551623. The reversal of 81292551620 is 2615529218.

It is not an unprimeable number, because it can be changed into a prime (81292551623) 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, 290330402 + ... + 290330681.

It is an arithmetic number, because the mean of its divisors is an integer number (8129255176).

Almost surely, 2^81292551620 is an apocalyptic number.

It is an amenable number.

81292551620 is an abundant number, since it is smaller than the sum of its proper divisors (113809572604).

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

81292551620 is a wasteful number, since it uses less digits than its factorization.

81292551620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 580661099 (or 580661097 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 41.

The spelling of 81292551620 in words is "eighty-one billion, two hundred ninety-two million, five hundred fifty-one thousand, six hundred twenty".