81616081600 has 42 divisors (see below), whose sum is σ = 200826574724. Its totient is φ = 32646432000.

The previous prime is 81616081571. The next prime is 81616081607. The reversal of 81616081600 is 618061618.

It is a happy number.

It is a super-2 number, since 2×81616081600² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81616081600.

It is not an unprimeable number, because it can be changed into a prime (81616081607) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 25503426 + ... + 25506625.

Almost surely, 2^81616081600 is an apocalyptic number.

81616081600 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81616081600 is an abundant number, since it is smaller than the sum of its proper divisors (119210493124).

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

81616081600 is a wasteful number, since it uses less digits than its factorization.

81616081600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51010073 (or 51010058 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 37.

The spelling of 81616081600 in words is "eighty-one billion, six hundred sixteen million, eighty-one thousand, six hundred".