21152239 has 2 divisors, whose sum is σ = 21152240. Its totient is φ = 21152238.

The previous prime is 21152237. The next prime is 21152291. The reversal of 21152239 is 93225112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21152239 - 2¹ = 21152237 is a prime.

Together with 21152237, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21152237) 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, 10576119 + 10576120.

It is an arithmetic number, because the mean of its divisors is an integer number (10576120).

Almost surely, 2^21152239 is an apocalyptic number.

21152239 is a deficient number, since it is larger than the sum of its proper divisors (1).

21152239 is an equidigital number, since it uses as much as digits as its factorization.

21152239 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1080, while the sum is 25.

The square root of 21152239 is about 4599.1563356772. The cubic root of 21152239 is about 276.5575048775.

The spelling of 21152239 in words is "twenty-one million, one hundred fifty-two thousand, two hundred thirty-nine".