18221481 has 12 divisors (see below), whose sum is σ = 26357760. Its totient is φ = 12130200.

The previous prime is 18221479. The next prime is 18221509. The reversal of 18221481 is 18412281.

18221481 is a `hidden beast` number, since 182 + 2 + 1 + 481 = 666.

It is not a de Polignac number, because 18221481 - 2¹ = 18221479 is a prime.

It is a super-2 number, since 2×18221481² = 664044739666722, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18221431) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9480 + ... + 11238.

It is an arithmetic number, because the mean of its divisors is an integer number (2196480).

Almost surely, 2^18221481 is an apocalyptic number.

It is an amenable number.

18221481 is a deficient number, since it is larger than the sum of its proper divisors (8136279).

18221481 is a wasteful number, since it uses less digits than its factorization.

18221481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2916 (or 2913 counting only the distinct ones).

The product of its digits is 1024, while the sum is 27.

The square root of 18221481 is about 4268.6626711419. The cubic root of 18221481 is about 263.1446577054.

The spelling of 18221481 in words is "eighteen million, two hundred twenty-one thousand, four hundred eighty-one".