21316437 has 12 divisors (see below), whose sum is σ = 31784064. Its totient is φ = 13752360.

The previous prime is 21316417. The next prime is 21316459. The reversal of 21316437 is 73461312.

21316437 is a `hidden beast` number, since 2 + 13 + 1 + 643 + 7 = 666.

It is not a de Polignac number, because 21316437 - 2¹² = 21312341 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21316437.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21316417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37923 + ... + 38480.

It is an arithmetic number, because the mean of its divisors is an integer number (2648672).

Almost surely, 2^21316437 is an apocalyptic number.

It is an amenable number.

21316437 is a deficient number, since it is larger than the sum of its proper divisors (10467627).

21316437 is a wasteful number, since it uses less digits than its factorization.

21316437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76440 (or 76437 counting only the distinct ones).

The product of its digits is 3024, while the sum is 27.

The square root of 21316437 is about 4616.9727094710. The cubic root of 21316437 is about 277.2712700061.

Adding to 21316437 its reverse (73461312), we get a palindrome (94777749).

The spelling of 21316437 in words is "twenty-one million, three hundred sixteen thousand, four hundred thirty-seven".