221538456 has 32 divisors (see below), whose sum is σ = 615385200. Its totient is φ = 73846080.

The previous prime is 221538439. The next prime is 221538469. The reversal of 221538456 is 654835122.

221538456 is a `hidden beast` number, since 221 + 5 + 384 + 56 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 221538456.

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, 512605 + ... + 513036.

Almost surely, 2^221538456 is an apocalyptic number.

It is an amenable number.

221538456 is an abundant number, since it is smaller than the sum of its proper divisors (393846744).

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

221538456 is a wasteful number, since it uses less digits than its factorization.

221538456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1025656 (or 1025646 counting only the distinct ones).

The product of its digits is 57600, while the sum is 36.

The square root of 221538456 is about 14884.1679646529. The cubic root of 221538456 is about 605.0849831671.

The spelling of 221538456 in words is "two hundred twenty-one million, five hundred thirty-eight thousand, four hundred fifty-six".