21752369 has 2 divisors, whose sum is σ = 21752370. Its totient is φ = 21752368.

The previous prime is 21752329. The next prime is 21752371. The reversal of 21752369 is 96325712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13601344 + 8151025 = 3688^2 + 2855^2 .

It is a cyclic number.

It is not a de Polignac number, because 21752369 - 2⁸ = 21752113 is a prime.

It is a super-2 number, since 2×21752369² = 946331114224322, which contains 22 as substring.

Together with 21752371, 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 (21752309) 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, 10876184 + 10876185.

It is an arithmetic number, because the mean of its divisors is an integer number (10876185).

Almost surely, 2^21752369 is an apocalyptic number.

It is an amenable number.

21752369 is a deficient number, since it is larger than the sum of its proper divisors (1).

21752369 is an equidigital number, since it uses as much as digits as its factorization.

21752369 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 35.

The square root of 21752369 is about 4663.9435030883. The cubic root of 21752369 is about 279.1486427610.

The spelling of 21752369 in words is "twenty-one million, seven hundred fifty-two thousand, three hundred sixty-nine".