81808157692800 has 2304 divisors, whose sum is σ = 388242684211200. Its totient is φ = 16450283520000.

The previous prime is 81808157692721. The next prime is 81808157692801. The reversal of 81808157692800 is 829675180818.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81808157692801) by changing a digit.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 2268586770 + ... + 2268622830.

Almost surely, 2^{81808157692800} is an apocalyptic number.

81808157692800 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81808157692800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (194121342105600).

81808157692800 is an abundant number, since it is smaller than the sum of its proper divisors (306434526518400).

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

81808157692800 is a wasteful number, since it uses less digits than its factorization.

81808157692800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36154 (or 36120 counting only the distinct ones).

The product of its (nonzero) digits is 15482880, while the sum is 63.

The spelling of 81808157692800 in words is "eighty-one trillion, eight hundred eight billion, one hundred fifty-seven million, six hundred ninety-two thousand, eight hundred".