21363537 has 16 divisors (see below), whose sum is σ = 30820608. Its totient is φ = 13084800.

The previous prime is 21363497. The next prime is 21363593. The reversal of 21363537 is 73536312.

It is not a de Polignac number, because 21363537 - 2⁷ = 21363409 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21363037) 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, 7912 + ... + 10262.

It is an arithmetic number, because the mean of its divisors is an integer number (1926288).

Almost surely, 2^21363537 is an apocalyptic number.

It is an amenable number.

21363537 is a deficient number, since it is larger than the sum of its proper divisors (9457071).

21363537 is a wasteful number, since it uses less digits than its factorization.

21363537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2600.

The product of its digits is 11340, while the sum is 30.

The square root of 21363537 is about 4622.0706398756. The cubic root of 21363537 is about 277.4753358487.

Adding to 21363537 its reverse (73536312), we get a palindrome (94899849).

The spelling of 21363537 in words is "twenty-one million, three hundred sixty-three thousand, five hundred thirty-seven".