21152399 has 2 divisors, whose sum is σ = 21152400. Its totient is φ = 21152398.

The previous prime is 21152381. The next prime is 21152413. The reversal of 21152399 is 99325112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21152399 - 2⁸ = 21152143 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21152309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10576199 + 10576200.

It is an arithmetic number, because the mean of its divisors is an integer number (10576200).

Almost surely, 2^21152399 is an apocalyptic number.

21152399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21152399 is an equidigital number, since it uses as much as digits as its factorization.

21152399 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4860, while the sum is 32.

The square root of 21152399 is about 4599.1737301389. The cubic root of 21152399 is about 276.5582021888.

The spelling of 21152399 in words is "twenty-one million, one hundred fifty-two thousand, three hundred ninety-nine".