21444165 has 24 divisors (see below), whose sum is σ = 38787840. Its totient is φ = 10939104.

The previous prime is 21444161. The next prime is 21444167. The reversal of 21444165 is 56144412.

21444165 is a `hidden beast` number, since 214 + 441 + 6 + 5 = 666.

It is not a de Polignac number, because 21444165 - 2² = 21444161 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444161) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9325 + ... + 11394.

It is an arithmetic number, because the mean of its divisors is an integer number (1616160).

Almost surely, 2^21444165 is an apocalyptic number.

It is an amenable number.

21444165 is a deficient number, since it is larger than the sum of its proper divisors (17343675).

21444165 is a wasteful number, since it uses less digits than its factorization.

21444165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20753 (or 20750 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 21444165 is about 4630.7844907748. The cubic root of 21444165 is about 277.8239703033.

Adding to 21444165 its reverse (56144412), we get a palindrome (77588577).

It can be divided in two parts, 21444 and 165, that added together give a square (21609 = 147²).

The spelling of 21444165 in words is "twenty-one million, four hundred forty-four thousand, one hundred sixty-five".