18522581 has 16 divisors (see below), whose sum is σ = 23200128. Its totient is φ = 14366400.

The previous prime is 18522557. The next prime is 18522583.

It is a happy number.

18522581 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 18522581 - 2¹⁴ = 18506197 is a prime.

It is a super-2 number, since 2×18522581² = 686172013803122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18522583) 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, 22151 + ... + 22971.

It is an arithmetic number, because the mean of its divisors is an integer number (1450008).

Almost surely, 2^18522581 is an apocalyptic number.

18522581 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18522581 is a deficient number, since it is larger than the sum of its proper divisors (4677547).

18522581 is a wasteful number, since it uses less digits than its factorization.

18522581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1132.

The product of its digits is 6400, while the sum is 32.

The square root of 18522581 is about 4303.7868209288. The cubic root of 18522581 is about 264.5861869423.

The spelling of 18522581 in words is "eighteen million, five hundred twenty-two thousand, five hundred eighty-one".