18227581 has 4 divisors (see below), whose sum is σ = 18243072. Its totient is φ = 18212092.

The previous prime is 18227537. The next prime is 18227611. The reversal of 18227581 is 18572281.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18227581 - 2¹⁹ = 17703293 is a prime.

It is a super-2 number, since 2×18227581² = 664489418223122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18227501) 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, 5821 + ... + 8386.

It is an arithmetic number, because the mean of its divisors is an integer number (4560768).

Almost surely, 2^18227581 is an apocalyptic number.

It is an amenable number.

18227581 is a deficient number, since it is larger than the sum of its proper divisors (15491).

18227581 is a wasteful number, since it uses less digits than its factorization.

18227581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15490.

The product of its digits is 8960, while the sum is 34.

The square root of 18227581 is about 4269.3771208456. The cubic root of 18227581 is about 263.1740187166.

The spelling of 18227581 in words is "eighteen million, two hundred twenty-seven thousand, five hundred eighty-one".