81610517636 has 6 divisors (see below), whose sum is σ = 142818405870. Its totient is φ = 40805258816.

The previous prime is 81610517629. The next prime is 81610517641. The reversal of 81610517636 is 63671501618.

It can be written as a sum of positive squares in only one way, i.e., 81449735236 + 160782400 = 285394^2 + 12680^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10201314701 + ... + 10201314708.

It is an arithmetic number, because the mean of its divisors is an integer number (23803067645).

Almost surely, 2^81610517636 is an apocalyptic number.

It is an amenable number.

81610517636 is a deficient number, since it is larger than the sum of its proper divisors (61207888234).

81610517636 is a wasteful number, since it uses less digits than its factorization.

81610517636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20402629413 (or 20402629411 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 44.

The spelling of 81610517636 in words is "eighty-one billion, six hundred ten million, five hundred seventeen thousand, six hundred thirty-six".