221856560 has 20 divisors (see below), whose sum is σ = 515816688. Its totient is φ = 88742592.

The previous prime is 221856527. The next prime is 221856581. The reversal of 221856560 is 65658122.

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 221856560.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1386524 + ... + 1386683.

Almost surely, 2^221856560 is an apocalyptic number.

221856560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221856560 is an abundant number, since it is smaller than the sum of its proper divisors (293960128).

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

221856560 is a wasteful number, since it uses less digits than its factorization.

221856560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2773220 (or 2773214 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 35.

The square root of 221856560 is about 14894.8501167350. The cubic root of 221856560 is about 605.3744557098.

The spelling of 221856560 in words is "two hundred twenty-one million, eight hundred fifty-six thousand, five hundred sixty".