21300537 has 4 divisors (see below), whose sum is σ = 28400720. Its totient is φ = 14200356.

The previous prime is 21300527. The next prime is 21300551. The reversal of 21300537 is 73500312.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21300537 - 2¹¹ = 21298489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21300527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3550087 + ... + 3550092.

It is an arithmetic number, because the mean of its divisors is an integer number (7100180).

Almost surely, 2^21300537 is an apocalyptic number.

It is an amenable number.

21300537 is a deficient number, since it is larger than the sum of its proper divisors (7100183).

21300537 is an equidigital number, since it uses as much as digits as its factorization.

21300537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7100182.

The product of its (nonzero) digits is 630, while the sum is 21.

The square root of 21300537 is about 4615.2504807432. The cubic root of 21300537 is about 277.2023136763.

Adding to 21300537 its reverse (73500312), we get a palindrome (94800849).

The spelling of 21300537 in words is "twenty-one million, three hundred thousand, five hundred thirty-seven".