21173417 has 2 divisors, whose sum is σ = 21173418. Its totient is φ = 21173416.

The previous prime is 21173413. The next prime is 21173419. The reversal of 21173417 is 71437112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19545241 + 1628176 = 4421^2 + 1276^2 .

It is a cyclic number.

It is not a de Polignac number, because 21173417 - 2² = 21173413 is a prime.

Together with 21173419, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21173413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10586708 + 10586709.

It is an arithmetic number, because the mean of its divisors is an integer number (10586709).

Almost surely, 2^21173417 is an apocalyptic number.

It is an amenable number.

21173417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21173417 is an equidigital number, since it uses as much as digits as its factorization.

21173417 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1176, while the sum is 26.

The square root of 21173417 is about 4601.4581384600. The cubic root of 21173417 is about 276.6497721978.

The spelling of 21173417 in words is "twenty-one million, one hundred seventy-three thousand, four hundred seventeen".