90121731685 has 8 divisors (see below), whose sum is σ = 111634661376. Its totient is φ = 69771663120.

The previous prime is 90121731677. The next prime is 90121731701. The reversal of 90121731685 is 58613712109.

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

It is not a de Polignac number, because 90121731685 - 2³ = 90121731677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 290715109 + ... + 290715418.

It is an arithmetic number, because the mean of its divisors is an integer number (13954332672).

Almost surely, 2^90121731685 is an apocalyptic number.

It is an amenable number.

90121731685 is a deficient number, since it is larger than the sum of its proper divisors (21512929691).

90121731685 is a wasteful number, since it uses less digits than its factorization.

90121731685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 581430563.

The product of its (nonzero) digits is 90720, while the sum is 43.

The spelling of 90121731685 in words is "ninety billion, one hundred twenty-one million, seven hundred thirty-one thousand, six hundred eighty-five".