81521175337 has 16 divisors (see below), whose sum is σ = 93758401152. Its totient is φ = 69433015680.

The previous prime is 81521175313. The next prime is 81521175343. The reversal of 81521175337 is 73357112518.

It is not a de Polignac number, because 81521175337 - 2²⁷ = 81386957609 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81521175293 and 81521175302.

It is not an unprimeable number, because it can be changed into a prime (81521175937) by changing a digit.

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, 749923 + ... + 851719.

It is an arithmetic number, because the mean of its divisors is an integer number (5859900072).

Almost surely, 2^81521175337 is an apocalyptic number.

It is an amenable number.

81521175337 is a deficient number, since it is larger than the sum of its proper divisors (12237225815).

81521175337 is a wasteful number, since it uses less digits than its factorization.

81521175337 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102528.

The product of its digits is 176400, while the sum is 43.

The spelling of 81521175337 in words is "eighty-one billion, five hundred twenty-one million, one hundred seventy-five thousand, three hundred thirty-seven".