21366535 has 16 divisors (see below), whose sum is σ = 27814752. Its totient is φ = 15692800.

The previous prime is 21366511. The next prime is 21366539. The reversal of 21366535 is 53566312.

It is not a de Polignac number, because 21366535 - 2⁵ = 21366503 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21366497 and 21366506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21366539) 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, 420 + ... + 6550.

It is an arithmetic number, because the mean of its divisors is an integer number (1738422).

Almost surely, 2^21366535 is an apocalyptic number.

21366535 is a deficient number, since it is larger than the sum of its proper divisors (6448217).

21366535 is a wasteful number, since it uses less digits than its factorization.

21366535 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6194.

The product of its digits is 16200, while the sum is 31.

The square root of 21366535 is about 4622.3949420187. The cubic root of 21366535 is about 277.4883148503.

The spelling of 21366535 in words is "twenty-one million, three hundred sixty-six thousand, five hundred thirty-five".