21227556 has 24 divisors (see below), whose sum is σ = 56607040. Its totient is φ = 6064992.

The previous prime is 21227533. The next prime is 21227561. The reversal of 21227556 is 65572212.

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, 126271 + ... + 126438.

Almost surely, 2^21227556 is an apocalyptic number.

It is an amenable number.

21227556 is an abundant number, since it is smaller than the sum of its proper divisors (35379484).

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

21227556 is a wasteful number, since it uses less digits than its factorization.

21227556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252723 (or 252721 counting only the distinct ones).

The product of its digits is 8400, while the sum is 30.

The square root of 21227556 is about 4607.3371919147. The cubic root of 21227556 is about 276.8853631214.

Adding to 21227556 its reverse (65572212), we get a palindrome (86799768).

The spelling of 21227556 in words is "twenty-one million, two hundred twenty-seven thousand, five hundred fifty-six".