21317373 has 48 divisors (see below), whose sum is σ = 40435200. Its totient is φ = 10484640.

The previous prime is 21317357. The next prime is 21317377. The reversal of 21317373 is 37371312.

It is not a de Polignac number, because 21317373 - 2⁴ = 21317357 is a prime.

It is a super-2 number, since 2×21317373² = 908860783242258, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21317377) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12358 + ... + 13976.

It is an arithmetic number, because the mean of its divisors is an integer number (842400).

Almost surely, 2^21317373 is an apocalyptic number.

It is an amenable number.

21317373 is a deficient number, since it is larger than the sum of its proper divisors (19117827).

21317373 is a wasteful number, since it uses less digits than its factorization.

21317373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1662 (or 1659 counting only the distinct ones).

The product of its digits is 2646, while the sum is 27.

The square root of 21317373 is about 4617.0740734799. The cubic root of 21317373 is about 277.2753282533.

Adding to 21317373 its reverse (37371312), we get a palindrome (58688685).

The spelling of 21317373 in words is "twenty-one million, three hundred seventeen thousand, three hundred seventy-three".