81568154979 has 30 divisors (see below), whose sum is σ = 122395284396. Its totient is φ = 54135081000.

The previous prime is 81568154939. The next prime is 81568155059. The reversal of 81568154979 is 97945186518.

81568154979 is a `hidden beast` number, since 8 + 1 + 5 + 6 + 81 + 549 + 7 + 9 = 666.

It is not a de Polignac number, because 81568154979 - 2¹³ = 81568146787 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81568154929) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 40721992 + ... + 40723994.

Almost surely, 2^81568154979 is an apocalyptic number.

81568154979 is a deficient number, since it is larger than the sum of its proper divisors (40827129417).

81568154979 is an frugal number, since it uses more digits than its factorization.

81568154979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4269 (or 2257 counting only the distinct ones).

The product of its digits is 21772800, while the sum is 63.

The spelling of 81568154979 in words is "eighty-one billion, five hundred sixty-eight million, one hundred fifty-four thousand, nine hundred seventy-nine".