21946365 has 72 divisors (see below), whose sum is σ = 45615960. Its totient is φ = 9725184.

The previous prime is 21946333. The next prime is 21946369. The reversal of 21946365 is 56364912.

It is a happy number.

21946365 is a `hidden beast` number, since 2 + 19 + 4 + 636 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1750329 + 20196036 = 1323^2 + 4494^2 .

It is not a de Polignac number, because 21946365 - 2⁵ = 21946333 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21946369) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 81451 + ... + 81719.

It is an arithmetic number, because the mean of its divisors is an integer number (633555).

Almost surely, 2^21946365 is an apocalyptic number.

It is an amenable number.

21946365 is an abundant number, since it is smaller than the sum of its proper divisors (23669595).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21946365 is a wasteful number, since it uses less digits than its factorization.

21946365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331 (or 321 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 21946365 is about 4684.6947606007. The cubic root of 21946365 is about 279.9760396164.

The spelling of 21946365 in words is "twenty-one million, nine hundred forty-six thousand, three hundred sixty-five".