221865990 has 32 divisors (see below), whose sum is σ = 534110976. Its totient is φ = 58982880.

The previous prime is 221865989. The next prime is 221866033. The reversal of 221865990 is 99568122.

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, 1242 + ... + 21101.

It is an arithmetic number, because the mean of its divisors is an integer number (16690968).

Almost surely, 2^221865990 is an apocalyptic number.

221865990 is an abundant number, since it is smaller than the sum of its proper divisors (312244986).

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

221865990 is a wasteful number, since it uses less digits than its factorization.

221865990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22684.

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 221865990 is about 14895.1666657342. The cubic root of 221865990 is about 605.3830327234.

The spelling of 221865990 in words is "two hundred twenty-one million, eight hundred sixty-five thousand, nine hundred ninety".