21319169 has 2 divisors, whose sum is σ = 21319170. Its totient is φ = 21319168.

The previous prime is 21319127. The next prime is 21319171. The reversal of 21319169 is 96191312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20295025 + 1024144 = 4505^2 + 1012^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21319169 is a prime.

It is a super-2 number, since 2×21319169² = 909013933701122, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 21319171, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21319769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10659584 + 10659585.

It is an arithmetic number, because the mean of its divisors is an integer number (10659585).

Almost surely, 2^21319169 is an apocalyptic number.

It is an amenable number.

21319169 is a deficient number, since it is larger than the sum of its proper divisors (1).

21319169 is an equidigital number, since it uses as much as digits as its factorization.

21319169 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916, while the sum is 32.

The square root of 21319169 is about 4617.2685648552. The cubic root of 21319169 is about 277.2831148992.

The spelling of 21319169 in words is "twenty-one million, three hundred nineteen thousand, one hundred sixty-nine".