221256556 has 12 divisors (see below), whose sum is σ = 394504992. Its totient is φ = 108540848.

The previous prime is 221256533. The next prime is 221256571. The reversal of 221256556 is 655652122.

It is a super-2 number, since 2×221256556² = 97908927145962272, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 521620 + ... + 522043.

It is an arithmetic number, because the mean of its divisors is an integer number (32875416).

Almost surely, 2^221256556 is an apocalyptic number.

It is an amenable number.

221256556 is a deficient number, since it is larger than the sum of its proper divisors (173248436).

221256556 is a wasteful number, since it uses less digits than its factorization.

221256556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1043720 (or 1043718 counting only the distinct ones).

The product of its digits is 36000, while the sum is 34.

The square root of 221256556 is about 14874.6951565402. The cubic root of 221256556 is about 604.8282243472.

The spelling of 221256556 in words is "two hundred twenty-one million, two hundred fifty-six thousand, five hundred fifty-six".