21417169 has 2 divisors, whose sum is σ = 21417170. Its totient is φ = 21417168.

The previous prime is 21417131. The next prime is 21417181. The reversal of 21417169 is 96171412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16524225 + 4892944 = 4065^2 + 2212^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21417169 is a prime.

It is a super-2 number, since 2×21417169² = 917390255949122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21417169.

It is not a weakly prime, because it can be changed into another prime (21417269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10708584 + 10708585.

It is an arithmetic number, because the mean of its divisors is an integer number (10708585).

Almost surely, 2^21417169 is an apocalyptic number.

It is an amenable number.

21417169 is a deficient number, since it is larger than the sum of its proper divisors (1).

21417169 is an equidigital number, since it uses as much as digits as its factorization.

21417169 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 31.

The square root of 21417169 is about 4627.8687319327. The cubic root of 21417169 is about 277.7073374040.

The spelling of 21417169 in words is "twenty-one million, four hundred seventeen thousand, one hundred sixty-nine".