21337631 has 8 divisors (see below), whose sum is σ = 24421920. Its totient is φ = 18262368.

The previous prime is 21337621. The next prime is 21337633. The reversal of 21337631 is 13673312.

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 21337631 - 2¹⁸ = 21075487 is a prime.

It is a super-2 number, since 2×21337631² = 910588993384322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21337631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21337633) 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, 3965 + ... + 7641.

It is an arithmetic number, because the mean of its divisors is an integer number (3052740).

Almost surely, 2^21337631 is an apocalyptic number.

21337631 is a deficient number, since it is larger than the sum of its proper divisors (3084289).

21337631 is an equidigital number, since it uses as much as digits as its factorization.

21337631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4513.

The product of its digits is 2268, while the sum is 26.

The square root of 21337631 is about 4619.2673661523. The cubic root of 21337631 is about 277.3631324625.

The spelling of 21337631 in words is "twenty-one million, three hundred thirty-seven thousand, six hundred thirty-one".