81605144922 has 32 divisors (see below), whose sum is σ = 188887142400. Its totient is φ = 23020618608.

The previous prime is 81605144869. The next prime is 81605144927. The reversal of 81605144922 is 22944150618.

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

It is not an unprimeable number, because it can be changed into a prime (81605144927) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12294022 + ... + 12300657.

It is an arithmetic number, because the mean of its divisors is an integer number (5902723200).

Almost surely, 2^81605144922 is an apocalyptic number.

81605144922 is an abundant number, since it is smaller than the sum of its proper divisors (107281997478).

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

81605144922 is a wasteful number, since it uses less digits than its factorization.

81605144922 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24594770.

The product of its (nonzero) digits is 138240, while the sum is 42.

The spelling of 81605144922 in words is "eighty-one billion, six hundred five million, one hundred forty-four thousand, nine hundred twenty-two".