81755558400 has 120 divisors (see below), whose sum is σ = 270074504304. Its totient is φ = 21801472000.

The previous prime is 81755558321. The next prime is 81755558411. The reversal of 81755558400 is 485555718.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 81755558400.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1026126 + ... + 1102925.

Almost surely, 2^81755558400 is an apocalyptic number.

81755558400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81755558400 is an abundant number, since it is smaller than the sum of its proper divisors (188318945904).

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

81755558400 is a wasteful number, since it uses less digits than its factorization.

81755558400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2129082 (or 2129061 counting only the distinct ones).

The product of its (nonzero) digits is 1120000, while the sum is 48.

The spelling of 81755558400 in words is "eighty-one billion, seven hundred fifty-five million, five hundred fifty-eight thousand, four hundred".