221816959 has 16 divisors (see below), whose sum is σ = 273430080. Its totient is φ = 175230720.

The previous prime is 221816953. The next prime is 221816971. The reversal of 221816959 is 959618122.

It is not a de Polignac number, because 221816959 - 2⁵ = 221816927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221816953) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73227 + ... + 76195.

It is an arithmetic number, because the mean of its divisors is an integer number (17089380).

Almost surely, 2^221816959 is an apocalyptic number.

221816959 is a deficient number, since it is larger than the sum of its proper divisors (51613121).

221816959 is a wasteful number, since it uses less digits than its factorization.

221816959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3810.

The product of its digits is 77760, while the sum is 43.

The square root of 221816959 is about 14893.5207053269. The cubic root of 221816959 is about 605.3384341464.

The spelling of 221816959 in words is "two hundred twenty-one million, eight hundred sixteen thousand, nine hundred fifty-nine".