16221556 has 48 divisors (see below), whose sum is σ = 32739840. Its totient is φ = 6975360.

The previous prime is 16221529. The next prime is 16221563. The reversal of 16221556 is 65512261.

It is a super-2 number, since 2×16221556² = 526277758122272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46575 + ... + 46921.

It is an arithmetic number, because the mean of its divisors is an integer number (682080).

Almost surely, 2^16221556 is an apocalyptic number.

It is an amenable number.

16221556 is an abundant number, since it is smaller than the sum of its proper divisors (16518284).

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

16221556 is a wasteful number, since it uses less digits than its factorization.

16221556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424 (or 422 counting only the distinct ones).

The product of its digits is 3600, while the sum is 28.

The square root of 16221556 is about 4027.5992849339. The cubic root of 16221556 is about 253.1419784577.

The spelling of 16221556 in words is "sixteen million, two hundred twenty-one thousand, five hundred fifty-six".