81709481700 has 1152 divisors, whose sum is σ = 353377382400. Its totient is φ = 15676416000.

The previous prime is 81709481617. The next prime is 81709481713. The reversal of 81709481700 is 718490718.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 215592111 + ... + 215592489.

It is an arithmetic number, because the mean of its divisors is an integer number (306751200).

Almost surely, 2^81709481700 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81709481700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (176688691200).

81709481700 is an abundant number, since it is smaller than the sum of its proper divisors (271667900700).

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

81709481700 is a wasteful number, since it uses less digits than its factorization.

81709481700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 498 (or 485 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 45.

The spelling of 81709481700 in words is "eighty-one billion, seven hundred nine million, four hundred eighty-one thousand, seven hundred".