81772605600 has 144 divisors (see below), whose sum is σ = 304194155328. Its totient is φ = 18690877440.

The previous prime is 81772605559. The next prime is 81772605647. The reversal of 81772605600 is 650627718.

It is a super-2 number, since 2×81772605600² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

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 23 ways as a sum of consecutive naturals, for example, 2416909 + ... + 2450508.

It is an arithmetic number, because the mean of its divisors is an integer number (2112459412).

Almost surely, 2^81772605600 is an apocalyptic number.

81772605600 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81772605600 is an abundant number, since it is smaller than the sum of its proper divisors (222421549728).

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

81772605600 is a wasteful number, since it uses less digits than its factorization.

81772605600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4867447 (or 4867434 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 42.

The spelling of 81772605600 in words is "eighty-one billion, seven hundred seventy-two million, six hundred five thousand, six hundred".