18990531 has 20 divisors (see below), whose sum is σ = 32422192. Its totient is φ = 10851408.

The previous prime is 18990523. The next prime is 18990539. The reversal of 18990531 is 13509981.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (18990523) and next prime (18990539).

It is not a de Polignac number, because 18990531 - 2³ = 18990523 is a prime.

It is a super-2 number, since 2×18990531² = 721280535323922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18990539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 16180 + ... + 17313.

Almost surely, 2^18990531 is an apocalyptic number.

18990531 is a deficient number, since it is larger than the sum of its proper divisors (13431661).

18990531 is an equidigital number, since it uses as much as digits as its factorization.

18990531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33512 (or 33503 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 36.

The square root of 18990531 is about 4357.8126393869. The cubic root of 18990531 is about 266.7958292690.

The spelling of 18990531 in words is "eighteen million, nine hundred ninety thousand, five hundred thirty-one".