21290713 has 4 divisors (see below), whose sum is σ = 21344740. Its totient is φ = 21236688.

The previous prime is 21290701. The next prime is 21290729. The reversal of 21290713 is 31709212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17707264 + 3583449 = 4208^2 + 1893^2 .

It is a cyclic number.

It is not a de Polignac number, because 21290713 - 2¹⁷ = 21159641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21290743) 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, 26418 + ... + 27211.

It is an arithmetic number, because the mean of its divisors is an integer number (5336185).

Almost surely, 2^21290713 is an apocalyptic number.

It is an amenable number.

21290713 is a deficient number, since it is larger than the sum of its proper divisors (54027).

21290713 is an equidigital number, since it uses as much as digits as its factorization.

21290713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54026.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 21290713 is about 4614.1860604011. The cubic root of 21290713 is about 277.1596910529.

Adding to 21290713 its reverse (31709212), we get a palindrome (52999925).

The spelling of 21290713 in words is "twenty-one million, two hundred ninety thousand, seven hundred thirteen".