21372269 has 2 divisors, whose sum is σ = 21372270. Its totient is φ = 21372268.

The previous prime is 21372233. The next prime is 21372271. The reversal of 21372269 is 96227312.

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., 13875625 + 7496644 = 3725^2 + 2738^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21372269 is a prime.

It is a super-2 number, since 2×21372269² = 913547764416722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 21372271, it forms a pair of twin primes.

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 (21372229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10686134 + 10686135.

It is an arithmetic number, because the mean of its divisors is an integer number (10686135).

Almost surely, 2^21372269 is an apocalyptic number.

It is an amenable number.

21372269 is a deficient number, since it is larger than the sum of its proper divisors (1).

21372269 is an equidigital number, since it uses as much as digits as its factorization.

21372269 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 32.

The square root of 21372269 is about 4623.0151416581. The cubic root of 21372269 is about 277.5131352168.

The spelling of 21372269 in words is "twenty-one million, three hundred seventy-two thousand, two hundred sixty-nine".