21317307 has 8 divisors (see below), whose sum is σ = 31007040. Its totient is φ = 12919560.

The previous prime is 21317267. The next prime is 21317327. The reversal of 21317307 is 70371312.

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

It is not a de Polignac number, because 21317307 - 2²⁴ = 4540091 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21317327) 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, 322957 + ... + 323022.

It is an arithmetic number, because the mean of its divisors is an integer number (3875880).

Almost surely, 2^21317307 is an apocalyptic number.

21317307 is a deficient number, since it is larger than the sum of its proper divisors (9689733).

21317307 is a wasteful number, since it uses less digits than its factorization.

21317307 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645993.

The product of its (nonzero) digits is 882, while the sum is 24.

The square root of 21317307 is about 4617.0669260906. The cubic root of 21317307 is about 277.2750420987.

Adding to 21317307 its reverse (70371312), we get a palindrome (91688619).

The spelling of 21317307 in words is "twenty-one million, three hundred seventeen thousand, three hundred seven".