81996616 has 16 divisors (see below), whose sum is σ = 165570300. Its totient is φ = 37844544.

The previous prime is 81996611. The next prime is 81996617. The reversal of 81996616 is 61669918.

It can be written as a sum of positive squares in 2 ways, for example, as 80174116 + 1822500 = 8954^2 + 1350^2 .

It is not an unprimeable number, because it can be changed into a prime (81996611) 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, 394111 + ... + 394318.

Almost surely, 2^81996616 is an apocalyptic number.

It is an amenable number.

81996616 is an abundant number, since it is smaller than the sum of its proper divisors (83573684).

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

81996616 is a wasteful number, since it uses less digits than its factorization.

81996616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 788448 (or 788444 counting only the distinct ones).

The product of its digits is 139968, while the sum is 46.

The square root of 81996616 is about 9055.1982860675. The cubic root of 81996616 is about 434.4421721835.

The spelling of 81996616 in words is "eighty-one million, nine hundred ninety-six thousand, six hundred sixteen".