21276317 has 2 divisors, whose sum is σ = 21276318. Its totient is φ = 21276316.

The previous prime is 21276287. The next prime is 21276329. The reversal of 21276317 is 71367212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19483396 + 1792921 = 4414^2 + 1339^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21276317 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21276317.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21276337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10638158 + 10638159.

It is an arithmetic number, because the mean of its divisors is an integer number (10638159).

Almost surely, 2^21276317 is an apocalyptic number.

It is an amenable number.

21276317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21276317 is an equidigital number, since it uses as much as digits as its factorization.

21276317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3528, while the sum is 29.

The square root of 21276317 is about 4612.6258248421. The cubic root of 21276317 is about 277.0972085589.

The spelling of 21276317 in words is "twenty-one million, two hundred seventy-six thousand, three hundred seventeen".