90821731 has 16 divisors (see below), whose sum is σ = 121943808. Its totient is φ = 65325600.

The previous prime is 90821711. The next prime is 90821737. The reversal of 90821731 is 13712809.

It is a cyclic number.

It is not a de Polignac number, because 90821731 - 2⁹ = 90821219 is a prime.

It is a super-2 number, since 2×90821731² = 16497173643672722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 90821693 and 90821702.

It is not an unprimeable number, because it can be changed into a prime (90821737) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44365 + ... + 46366.

It is an arithmetic number, because the mean of its divisors is an integer number (7621488).

Almost surely, 2^90821731 is an apocalyptic number.

90821731 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

90821731 is a deficient number, since it is larger than the sum of its proper divisors (31122077).

90821731 is a wasteful number, since it uses less digits than its factorization.

90821731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90762.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 90821731 is about 9530.0435990608. The cubic root of 90821731 is about 449.5002369459.

The spelling of 90821731 in words is "ninety million, eight hundred twenty-one thousand, seven hundred thirty-one".