21380269 has 2 divisors, whose sum is σ = 21380270. Its totient is φ = 21380268.

The previous prime is 21380267. The next prime is 21380273. The reversal of 21380269 is 96208312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18275625 + 3104644 = 4275^2 + 1762^2 .

It is a cyclic number.

It is not a de Polignac number, because 21380269 - 2¹ = 21380267 is a prime.

It is a super-2 number, since 2×21380269² = 914231805024722, which contains 22 as substring.

Together with 21380267, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21380269.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21380267) 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, 10690134 + 10690135.

It is an arithmetic number, because the mean of its divisors is an integer number (10690135).

Almost surely, 2^21380269 is an apocalyptic number.

It is an amenable number.

21380269 is a deficient number, since it is larger than the sum of its proper divisors (1).

21380269 is an equidigital number, since it uses as much as digits as its factorization.

21380269 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 21380269 is about 4623.8802968935. The cubic root of 21380269 is about 277.5477568431.

The spelling of 21380269 in words is "twenty-one million, three hundred eighty thousand, two hundred sixty-nine".