21913365 has 32 divisors (see below), whose sum is σ = 38522880. Its totient is φ = 10587456.

The previous prime is 21913363. The next prime is 21913379. The reversal of 21913365 is 56331912.

It is not a de Polignac number, because 21913365 - 2¹ = 21913363 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21913363) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4884 + ... + 8226.

It is an arithmetic number, because the mean of its divisors is an integer number (1203840).

Almost surely, 2^21913365 is an apocalyptic number.

It is an amenable number.

21913365 is a deficient number, since it is larger than the sum of its proper divisors (16609515).

21913365 is a wasteful number, since it uses less digits than its factorization.

21913365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3393.

The product of its digits is 4860, while the sum is 30.

The square root of 21913365 is about 4681.1713277768. The cubic root of 21913365 is about 279.8356390827.

The spelling of 21913365 in words is "twenty-one million, nine hundred thirteen thousand, three hundred sixty-five".