221242665 has 16 divisors (see below), whose sum is σ = 404558208. Its totient is φ = 101139456.

The previous prime is 221242663. The next prime is 221242667. The reversal of 221242665 is 566242122.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (221242663) and next prime (221242667).

It is not a de Polignac number, because 221242665 - 2¹ = 221242663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221242663) 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, 1053432 + ... + 1053641.

It is an arithmetic number, because the mean of its divisors is an integer number (25284888).

Almost surely, 2^221242665 is an apocalyptic number.

It is an amenable number.

221242665 is a deficient number, since it is larger than the sum of its proper divisors (183315543).

221242665 is a wasteful number, since it uses less digits than its factorization.

221242665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2107088.

The product of its digits is 11520, while the sum is 30.

The square root of 221242665 is about 14874.2282152722. The cubic root of 221242665 is about 604.8155665759.

Adding to 221242665 its reverse (566242122), we get a palindrome (787484787).

The spelling of 221242665 in words is "two hundred twenty-one million, two hundred forty-two thousand, six hundred sixty-five".