90391531 has 4 divisors (see below), whose sum is σ = 95149000. Its totient is φ = 85634064.

The previous prime is 90391523. The next prime is 90391549. The reversal of 90391531 is 13519309.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13519309 = 379 ⋅35671.

It is not a de Polignac number, because 90391531 - 2³ = 90391523 is a prime.

It is a super-2 number, since 2×90391531² = 16341257753047922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 90391493 and 90391502.

It is not an unprimeable number, because it can be changed into a prime (90391501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2378706 + ... + 2378743.

It is an arithmetic number, because the mean of its divisors is an integer number (23787250).

Almost surely, 2^90391531 is an apocalyptic number.

90391531 is a deficient number, since it is larger than the sum of its proper divisors (4757469).

90391531 is a wasteful number, since it uses less digits than its factorization.

90391531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4757468.

The product of its (nonzero) digits is 3645, while the sum is 31.

The square root of 90391531 is about 9507.4460818876. The cubic root of 90391531 is about 448.7893897035.

The spelling of 90391531 in words is "ninety million, three hundred ninety-one thousand, five hundred thirty-one".