81557463735 has 64 divisors (see below), whose sum is σ = 160077980160. Its totient is φ = 39066531840.

The previous prime is 81557463707. The next prime is 81557463781. The reversal of 81557463735 is 53736475518.

81557463735 is a `hidden beast` number, since 8 + 1 + 5 + 574 + 6 + 37 + 35 = 666.

It is not a de Polignac number, because 81557463735 - 2⁵ = 81557463703 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 207594 + ... + 454103.

It is an arithmetic number, because the mean of its divisors is an integer number (2501218440).

Almost surely, 2^81557463735 is an apocalyptic number.

81557463735 is a deficient number, since it is larger than the sum of its proper divisors (78520516425).

81557463735 is a wasteful number, since it uses less digits than its factorization.

81557463735 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 661805 (or 661799 counting only the distinct ones).

The product of its digits is 10584000, while the sum is 54.

The spelling of 81557463735 in words is "eighty-one billion, five hundred fifty-seven million, four hundred sixty-three thousand, seven hundred thirty-five".