81610615641 has 16 divisors (see below), whose sum is σ = 110198491200. Its totient is φ = 53717587968.

The previous prime is 81610615631. The next prime is 81610615657. The reversal of 81610615641 is 14651601618.

It is not a de Polignac number, because 81610615641 - 2⁶ = 81610615577 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81610615641.

It is not an unprimeable number, because it can be changed into a prime (81610615631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 212736 + ... + 456593.

It is an arithmetic number, because the mean of its divisors is an integer number (6887405700).

Almost surely, 2^81610615641 is an apocalyptic number.

It is an amenable number.

81610615641 is a deficient number, since it is larger than the sum of its proper divisors (28587875559).

81610615641 is a wasteful number, since it uses less digits than its factorization.

81610615641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 669848.

The product of its (nonzero) digits is 34560, while the sum is 39.

The spelling of 81610615641 in words is "eighty-one billion, six hundred ten million, six hundred fifteen thousand, six hundred forty-one".