90831561 has 16 divisors (see below), whose sum is σ = 128441664. Its totient is φ = 56899584.

The previous prime is 90831539. The next prime is 90831569. The reversal of 90831561 is 16513809.

It is not a de Polignac number, because 90831561 - 2¹⁵ = 90798793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (90831569) 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, 44025 + ... + 46041.

It is an arithmetic number, because the mean of its divisors is an integer number (8027604).

Almost surely, 2^90831561 is an apocalyptic number.

It is an amenable number.

90831561 is a deficient number, since it is larger than the sum of its proper divisors (37610103).

90831561 is a wasteful number, since it uses less digits than its factorization.

90831561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2920.

The product of its (nonzero) digits is 6480, while the sum is 33.

The square root of 90831561 is about 9530.5593225162. The cubic root of 90831561 is about 449.5164534317.

The spelling of 90831561 in words is "ninety million, eight hundred thirty-one thousand, five hundred sixty-one".