18221156 has 24 divisors (see below), whose sum is σ = 32768064. Its totient is φ = 8862560.

The previous prime is 18221153. The next prime is 18221167. The reversal of 18221156 is 65112281.

It is not an unprimeable number, because it can be changed into a prime (18221153) 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, 23186 + ... + 23958.

It is an arithmetic number, because the mean of its divisors is an integer number (1365336).

Almost surely, 2^18221156 is an apocalyptic number.

It is an amenable number.

18221156 is a deficient number, since it is larger than the sum of its proper divisors (14546908).

18221156 is a wasteful number, since it uses less digits than its factorization.

18221156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 931 (or 929 counting only the distinct ones).

The product of its digits is 960, while the sum is 26.

The square root of 18221156 is about 4268.6246028434. The cubic root of 18221156 is about 263.1430932054.

The spelling of 18221156 in words is "eighteen million, two hundred twenty-one thousand, one hundred fifty-six".