221622661 has 4 divisors (see below), whose sum is σ = 238670572. Its totient is φ = 204574752.

The previous prime is 221622647. The next prime is 221622683. The reversal of 221622661 is 166226122.

221622661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 47541025 + 174081636 = 6895^2 + 13194^2 .

It is a cyclic number.

It is not a de Polignac number, because 221622661 - 2⁵ = 221622629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221622601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8523936 + ... + 8523961.

It is an arithmetic number, because the mean of its divisors is an integer number (59667643).

Almost surely, 2^221622661 is an apocalyptic number.

It is an amenable number.

221622661 is a deficient number, since it is larger than the sum of its proper divisors (17047911).

221622661 is a wasteful number, since it uses less digits than its factorization.

221622661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17047910.

The product of its digits is 3456, while the sum is 28.

The square root of 221622661 is about 14886.9963726737. The cubic root of 221622661 is about 605.1616361147.

Adding to 221622661 its reverse (166226122), we get a palindrome (387848783).

The spelling of 221622661 in words is "two hundred twenty-one million, six hundred twenty-two thousand, six hundred sixty-one".