18221557232 has 40 divisors (see below), whose sum is σ = 37173811200. Its totient is φ = 8628610752.

The previous prime is 18221557199. The next prime is 18221557259. The reversal of 18221557232 is 23275512281.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1275473 + ... + 1289679.

It is an arithmetic number, because the mean of its divisors is an integer number (929345280).

Almost surely, 2^18221557232 is an apocalyptic number.

It is an amenable number.

18221557232 is an abundant number, since it is smaller than the sum of its proper divisors (18952253968).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18221557232 is a wasteful number, since it uses less digits than its factorization.

18221557232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18453 (or 18447 counting only the distinct ones).

The product of its digits is 67200, while the sum is 38.

The spelling of 18221557232 in words is "eighteen billion, two hundred twenty-one million, five hundred fifty-seven thousand, two hundred thirty-two".