81091413288 has 48 divisors (see below), whose sum is σ = 219637372500. Its totient is φ = 27028650240.

The previous prime is 81091413281. The next prime is 81091413311. The reversal of 81091413288 is 88231419018.

It can be written as a sum of positive squares in 2 ways, for example, as 70213340484 + 10878072804 = 264978^2 + 104298^2 .

It is not an unprimeable number, because it can be changed into a prime (81091413281) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1430118 + ... + 1485738.

Almost surely, 2^81091413288 is an apocalyptic number.

It is an amenable number.

81091413288 is an abundant number, since it is smaller than the sum of its proper divisors (138545959212).

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

81091413288 is a wasteful number, since it uses less digits than its factorization.

81091413288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75882 (or 75875 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 45.

The spelling of 81091413288 in words is "eighty-one billion, ninety-one million, four hundred thirteen thousand, two hundred eighty-eight".