81616899513 has 24 divisors (see below), whose sum is σ = 118724788672. Its totient is φ = 49826513664.

The previous prime is 81616899457. The next prime is 81616899517. The reversal of 81616899513 is 31599861618.

It is not a de Polignac number, because 81616899513 - 2¹² = 81616895417 is a prime.

It is a super-2 number, since 2×81616899513² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81616899517) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1240045 + ... + 1304202.

Almost surely, 2^81616899513 is an apocalyptic number.

It is an amenable number.

81616899513 is a deficient number, since it is larger than the sum of its proper divisors (37107889159).

81616899513 is a wasteful number, since it uses less digits than its factorization.

81616899513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2544321 (or 2544304 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 57.

The spelling of 81616899513 in words is "eighty-one billion, six hundred sixteen million, eight hundred ninety-nine thousand, five hundred thirteen".