81537690580 has 48 divisors (see below), whose sum is σ = 181705582800. Its totient is φ = 30628118528.

The previous prime is 81537690557. The next prime is 81537690593. The reversal of 81537690580 is 8509673518.

It can be written as a sum of positive squares in 8 ways, for example, as 30276 + 81537660304 = 174^2 + 285548^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 114397 + ... + 419716.

It is an arithmetic number, because the mean of its divisors is an integer number (3785532975).

Almost surely, 2^81537690580 is an apocalyptic number.

It is an amenable number.

81537690580 is an abundant number, since it is smaller than the sum of its proper divisors (100167892220).

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

81537690580 is a wasteful number, since it uses less digits than its factorization.

81537690580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 534588 (or 534586 counting only the distinct ones).

The product of its (nonzero) digits is 1814400, while the sum is 52.

The spelling of 81537690580 in words is "eighty-one billion, five hundred thirty-seven million, six hundred ninety thousand, five hundred eighty".