81712978858 has 16 divisors (see below), whose sum is σ = 140085766080. Its totient is φ = 35018254656.

The previous prime is 81712978847. The next prime is 81712978937. The reversal of 81712978858 is 85887921718.

It is a self number, because there is not a number n which added to its sum of digits gives 81712978858.

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, 217810 + ... + 459202.

It is an arithmetic number, because the mean of its divisors is an integer number (8755360380).

Almost surely, 2^81712978858 is an apocalyptic number.

81712978858 is a deficient number, since it is larger than the sum of its proper divisors (58372787222).

81712978858 is a wasteful number, since it uses less digits than its factorization.

81712978858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265581.

The product of its digits is 18063360, while the sum is 64.

The spelling of 81712978858 in words is "eighty-one billion, seven hundred twelve million, nine hundred seventy-eight thousand, eight hundred fifty-eight".