21317669 has 2 divisors, whose sum is σ = 21317670. Its totient is φ = 21317668.

The previous prime is 21317651. The next prime is 21317683. The reversal of 21317669 is 96671312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17850625 + 3467044 = 4225^2 + 1862^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21317669 is a prime.

It is a super-2 number, since 2×21317669² = 908886023187122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21317689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10658834 + 10658835.

It is an arithmetic number, because the mean of its divisors is an integer number (10658835).

Almost surely, 2^21317669 is an apocalyptic number.

It is an amenable number.

21317669 is a deficient number, since it is larger than the sum of its proper divisors (1).

21317669 is an equidigital number, since it uses as much as digits as its factorization.

21317669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13608, while the sum is 35.

The square root of 21317669 is about 4617.1061283016. The cubic root of 21317669 is about 277.2766116059.

The spelling of 21317669 in words is "twenty-one million, three hundred seventeen thousand, six hundred sixty-nine".