222165621 has 12 divisors (see below), whose sum is σ = 326345760. Its totient is φ = 145599720.

The previous prime is 222165583. The next prime is 222165637. The reversal of 222165621 is 126561222.

222165621 is a `hidden beast` number, since 2 + 2 + 2 + 1 + 656 + 2 + 1 = 666.

It is not a de Polignac number, because 222165621 - 2¹⁸ = 221903477 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (222165641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 208665 + ... + 209726.

It is an arithmetic number, because the mean of its divisors is an integer number (27195480).

Almost surely, 2^222165621 is an apocalyptic number.

It is an amenable number.

222165621 is a deficient number, since it is larger than the sum of its proper divisors (104180139).

222165621 is a wasteful number, since it uses less digits than its factorization.

222165621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418456 (or 418453 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 222165621 is about 14905.2212663885. The cubic root of 222165621 is about 605.6554342874.

The spelling of 222165621 in words is "two hundred twenty-two million, one hundred sixty-five thousand, six hundred twenty-one".