21293317 has 2 divisors, whose sum is σ = 21293318. Its totient is φ = 21293316.

The previous prime is 21293273. The next prime is 21293329. The reversal of 21293317 is 71339212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18887716 + 2405601 = 4346^2 + 1551^2 .

It is a cyclic number.

It is not a de Polignac number, because 21293317 - 2¹¹ = 21291269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21293347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646658 + 10646659.

It is an arithmetic number, because the mean of its divisors is an integer number (10646659).

Almost surely, 2^21293317 is an apocalyptic number.

It is an amenable number.

21293317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21293317 is an equidigital number, since it uses as much as digits as its factorization.

21293317 is an evil number, because the sum of its binary digits is even.

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

The square root of 21293317 is about 4614.4682250504. The cubic root of 21293317 is about 277.1709901017.

The spelling of 21293317 in words is "twenty-one million, two hundred ninety-three thousand, three hundred seventeen".