221664123 has 6 divisors (see below), whose sum is σ = 320181524. Its totient is φ = 147776076.

The previous prime is 221664119. The next prime is 221664161. The reversal of 221664123 is 321466122.

221664123 is a `hidden beast` number, since 2 + 2 + 16 + 641 + 2 + 3 = 666.

It is not a de Polignac number, because 221664123 - 2² = 221664119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221664103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12314665 + ... + 12314682.

Almost surely, 2^221664123 is an apocalyptic number.

221664123 is a deficient number, since it is larger than the sum of its proper divisors (98517401).

221664123 is a wasteful number, since it uses less digits than its factorization.

221664123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24629353 (or 24629350 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 221664123 is about 14888.3888651526. The cubic root of 221664123 is about 605.1993723990.

The spelling of 221664123 in words is "two hundred twenty-one million, six hundred sixty-four thousand, one hundred twenty-three".