21313237 has 8 divisors (see below), whose sum is σ = 23293440. Its totient is φ = 19340160.

The previous prime is 21313207. The next prime is 21313241. The reversal of 21313237 is 73231312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21313237 - 2²³ = 12924629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21313207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5964 + ... + 8842.

It is an arithmetic number, because the mean of its divisors is an integer number (2911680).

Almost surely, 2^21313237 is an apocalyptic number.

It is an amenable number.

21313237 is a deficient number, since it is larger than the sum of its proper divisors (1980203).

21313237 is a wasteful number, since it uses less digits than its factorization.

21313237 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3563.

The product of its digits is 756, while the sum is 22.

The square root of 21313237 is about 4616.6261490400. The cubic root of 21313237 is about 277.2573947594.

Adding to 21313237 its reverse (73231312), we get a palindrome (94544549).

The spelling of 21313237 in words is "twenty-one million, three hundred thirteen thousand, two hundred thirty-seven".