81520508160 has 1728 divisors, whose sum is σ = 379791552000. Its totient is φ = 16452108288.

The previous prime is 81520508143. The next prime is 81520508189. The reversal of 81520508160 is 6180502518.

81520508160 is a `hidden beast` number, since 8 + 1 + 520 + 50 + 81 + 6 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 3544369909 + ... + 3544369931.

Almost surely, 2^81520508160 is an apocalyptic number.

81520508160 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 81520508160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (189895776000).

81520508160 is an abundant number, since it is smaller than the sum of its proper divisors (298271043840).

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

81520508160 is a wasteful number, since it uses less digits than its factorization.

81520508160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 36.

The spelling of 81520508160 in words is "eighty-one billion, five hundred twenty million, five hundred eight thousand, one hundred sixty".