221661623 has 8 divisors (see below), whose sum is σ = 234831600. Its totient is φ = 208506240.

The previous prime is 221661611. The next prime is 221661631. The reversal of 221661623 is 326166122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221661623 - 2¹⁶ = 221596087 is a prime.

It is a super-2 number, since 2×221661623² = 98267750221988258, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221661673) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52028 + ... + 56126.

It is an arithmetic number, because the mean of its divisors is an integer number (29353950).

Almost surely, 2^221661623 is an apocalyptic number.

221661623 is a deficient number, since it is larger than the sum of its proper divisors (13169977).

221661623 is a wasteful number, since it uses less digits than its factorization.

221661623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7297.

The product of its digits is 5184, while the sum is 29.

The square root of 221661623 is about 14888.3049068724. The cubic root of 221661623 is about 605.1970971787.

The spelling of 221661623 in words is "two hundred twenty-one million, six hundred sixty-one thousand, six hundred twenty-three".