81281520456 has 32 divisors (see below), whose sum is σ = 203246309760. Its totient is φ = 27088172352.

The previous prime is 81281520403. The next prime is 81281520511. The reversal of 81281520456 is 65402518218.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 236320 + ... + 467343.

It is an arithmetic number, because the mean of its divisors is an integer number (6351447180).

Almost surely, 2^81281520456 is an apocalyptic number.

It is an amenable number.

81281520456 is an abundant number, since it is smaller than the sum of its proper divisors (121964789304).

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

81281520456 is a wasteful number, since it uses less digits than its factorization.

81281520456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708485 (or 708481 counting only the distinct ones).

The product of its (nonzero) digits is 153600, while the sum is 42.

The spelling of 81281520456 in words is "eighty-one billion, two hundred eighty-one million, five hundred twenty thousand, four hundred fifty-six".