81577508637 has 8 divisors (see below), whose sum is σ = 108810653536. Its totient is φ = 54364684752.

The previous prime is 81577508633. The next prime is 81577508651. The reversal of 81577508637 is 73680577518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81577508637 - 2² = 81577508633 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81577508633) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5070883 + ... + 5086944.

It is an arithmetic number, because the mean of its divisors is an integer number (13601331692).

Almost surely, 2^81577508637 is an apocalyptic number.

It is an amenable number.

81577508637 is a deficient number, since it is larger than the sum of its proper divisors (27233144899).

81577508637 is a wasteful number, since it uses less digits than its factorization.

81577508637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10160507.

The product of its (nonzero) digits is 9878400, while the sum is 57.

The spelling of 81577508637 in words is "eighty-one billion, five hundred seventy-seven million, five hundred eight thousand, six hundred thirty-seven".