21955165 has 8 divisors (see below), whose sum is σ = 27732960. Its totient is φ = 16639632.

The previous prime is 21955159. The next prime is 21955169. The reversal of 21955165 is 56155912.

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 21955165 - 2²³ = 13566557 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21955165.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21955169) 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, 115459 + ... + 115648.

It is an arithmetic number, because the mean of its divisors is an integer number (3466620).

Almost surely, 2^21955165 is an apocalyptic number.

It is an amenable number.

21955165 is a deficient number, since it is larger than the sum of its proper divisors (5777795).

21955165 is a wasteful number, since it uses less digits than its factorization.

21955165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231131.

The product of its digits is 13500, while the sum is 34.

The square root of 21955165 is about 4685.6338952163. The cubic root of 21955165 is about 280.0134559860.

The spelling of 21955165 in words is "twenty-one million, nine hundred fifty-five thousand, one hundred sixty-five".