81979715041 has 9 divisors (see below), whose sum is σ = 95366489841. Its totient is φ = 70266609252.

The previous prime is 81979715029. The next prime is 81979715063. The reversal of 81979715041 is 14051797918.

It is a happy number.

The square root of 81979715041 is 286321.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 81979715041 - 2⁹ = 81979714529 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81979715041.

It is not an unprimeable number, because it can be changed into a prime (81979715021) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1983796 + ... + 2024698.

It is an arithmetic number, because the mean of its divisors is an integer number (10596276649).

Almost surely, 2^81979715041 is an apocalyptic number.

81979715041 is the 286321-st square number.

81979715041 is the 143161-st centered octagonal number.

It is an amenable number.

81979715041 is a deficient number, since it is larger than the sum of its proper divisors (13386774800).

81979715041 is an frugal number, since it uses more digits than its factorization.

81979715041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81820 (or 40910 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 52.

The spelling of 81979715041 in words is "eighty-one billion, nine hundred seventy-nine million, seven hundred fifteen thousand, forty-one".