81957184656 has 20 divisors (see below), whose sum is σ = 211722727152. Its totient is φ = 27319061536.

The previous prime is 81957184601. The next prime is 81957184657. The reversal of 81957184656 is 65648175918.

It is a self number, because there is not a number n which added to its sum of digits gives 81957184656.

It is not an unprimeable number, because it can be changed into a prime (81957184657) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 853720626 + ... + 853720721.

Almost surely, 2^81957184656 is an apocalyptic number.

It is an amenable number.

81957184656 is an abundant number, since it is smaller than the sum of its proper divisors (129765542496).

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

81957184656 is a wasteful number, since it uses less digits than its factorization.

81957184656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1707441358 (or 1707441352 counting only the distinct ones).

The product of its digits is 14515200, while the sum is 60.

The spelling of 81957184656 in words is "eighty-one billion, nine hundred fifty-seven million, one hundred eighty-four thousand, six hundred fifty-six".