18221264 has 10 divisors (see below), whose sum is σ = 35303730. Its totient is φ = 9110624.

The previous prime is 18221257. The next prime is 18221339. The reversal of 18221264 is 46212281.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 16875664 + 1345600 = 4108^2 + 1160^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 569399 + ... + 569430.

It is an arithmetic number, because the mean of its divisors is an integer number (3530373).

Almost surely, 2^18221264 is an apocalyptic number.

It is an amenable number.

18221264 is a deficient number, since it is larger than the sum of its proper divisors (17082466).

18221264 is a wasteful number, since it uses less digits than its factorization.

18221264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1138837 (or 1138831 counting only the distinct ones).

The product of its digits is 1536, while the sum is 26.

The square root of 18221264 is about 4268.6372532695. The cubic root of 18221264 is about 263.1436131028.

The spelling of 18221264 in words is "eighteen million, two hundred twenty-one thousand, two hundred sixty-four".