21012713 has 4 divisors (see below), whose sum is σ = 21459840. Its totient is φ = 20565588.

The previous prime is 21012701. The next prime is 21012737. The reversal of 21012713 is 31721012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21012713 - 2⁸ = 21012457 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21012691 and 21012700.

It is not an unprimeable number, because it can be changed into a prime (21012743) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 223493 + ... + 223586.

It is an arithmetic number, because the mean of its divisors is an integer number (5364960).

Almost surely, 2^21012713 is an apocalyptic number.

It is an amenable number.

21012713 is a deficient number, since it is larger than the sum of its proper divisors (447127).

21012713 is an equidigital number, since it uses as much as digits as its factorization.

21012713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 447126.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 21012713 is about 4583.9625871074. The cubic root of 21012713 is about 275.9480797455.

Adding to 21012713 its reverse (31721012), we get a palindrome (52733725).

The spelling of 21012713 in words is "twenty-one million, twelve thousand, seven hundred thirteen".