81616478568 has 16 divisors (see below), whose sum is σ = 204041196480. Its totient is φ = 27205492848.

The previous prime is 81616478543. The next prime is 81616478621. The reversal of 81616478568 is 86587461618.

It is a happy number.

It is a super-3 number, since 3×81616478568³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1700343280 + ... + 1700343327.

It is an arithmetic number, because the mean of its divisors is an integer number (12752574780).

Almost surely, 2^81616478568 is an apocalyptic number.

It is an amenable number.

81616478568 is an abundant number, since it is smaller than the sum of its proper divisors (122424717912).

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

81616478568 is a wasteful number, since it uses less digits than its factorization.

81616478568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3400686616 (or 3400686612 counting only the distinct ones).

The product of its digits is 15482880, while the sum is 60.

The spelling of 81616478568 in words is "eighty-one billion, six hundred sixteen million, four hundred seventy-eight thousand, five hundred sixty-eight".