18220531 has 8 divisors (see below), whose sum is σ = 21729024. Its totient is φ = 14938440.

The previous prime is 18220513. The next prime is 18220561. The reversal of 18220531 is 13502281.

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

It is a cyclic number.

It is not a de Polignac number, because 18220531 - 2⁷ = 18220403 is a prime.

It is a super-2 number, since 2×18220531² = 663975499843922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18220511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56425 + ... + 56746.

It is an arithmetic number, because the mean of its divisors is an integer number (2716128).

Almost surely, 2^18220531 is an apocalyptic number.

18220531 is a deficient number, since it is larger than the sum of its proper divisors (3508493).

18220531 is a wasteful number, since it uses less digits than its factorization.

18220531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113201.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 18220531 is about 4268.5513936229. The cubic root of 18220531 is about 263.1400844992.

The spelling of 18220531 in words is "eighteen million, two hundred twenty thousand, five hundred thirty-one".