21392317 has 2 divisors, whose sum is σ = 21392318. Its totient is φ = 21392316.

The previous prime is 21392303. The next prime is 21392333. The reversal of 21392317 is 71329312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20169081 + 1223236 = 4491^2 + 1106^2 .

It is a cyclic number.

It is not a de Polignac number, because 21392317 - 2¹⁵ = 21359549 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21392017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10696158 + 10696159.

It is an arithmetic number, because the mean of its divisors is an integer number (10696159).

Almost surely, 2^21392317 is an apocalyptic number.

It is an amenable number.

21392317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21392317 is an equidigital number, since it uses as much as digits as its factorization.

21392317 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2268, while the sum is 28.

The square root of 21392317 is about 4625.1829153018. The cubic root of 21392317 is about 277.5998807190.

The spelling of 21392317 in words is "twenty-one million, three hundred ninety-two thousand, three hundred seventeen".