21307713 has 16 divisors (see below), whose sum is σ = 32787456. Its totient is φ = 12056400.

The previous prime is 21307687. The next prime is 21307753. The reversal of 21307713 is 31770312.

It is not a de Polignac number, because 21307713 - 2⁸ = 21307457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21307753) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2763 + ... + 7088.

It is an arithmetic number, because the mean of its divisors is an integer number (2049216).

Almost surely, 2^21307713 is an apocalyptic number.

It is an amenable number.

21307713 is a deficient number, since it is larger than the sum of its proper divisors (11479743).

21307713 is a wasteful number, since it uses less digits than its factorization.

21307713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9964.

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

The square root of 21307713 is about 4616.0278378710. The cubic root of 21307713 is about 277.2334393464.

The spelling of 21307713 in words is "twenty-one million, three hundred seven thousand, seven hundred thirteen".