21732317 has 2 divisors, whose sum is σ = 21732318. Its totient is φ = 21732316.

The previous prime is 21732253. The next prime is 21732323. The reversal of 21732317 is 71323712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21724921 + 7396 = 4661^2 + 86^2 .

It is a cyclic number.

It is not a de Polignac number, because 21732317 - 2⁶ = 21732253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21732017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10866158 + 10866159.

It is an arithmetic number, because the mean of its divisors is an integer number (10866159).

Almost surely, 2^21732317 is an apocalyptic number.

It is an amenable number.

21732317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21732317 is an equidigital number, since it uses as much as digits as its factorization.

21732317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1764, while the sum is 26.

The square root of 21732317 is about 4661.7933244622. The cubic root of 21732317 is about 279.0628404675.

The spelling of 21732317 in words is "twenty-one million, seven hundred thirty-two thousand, three hundred seventeen".