21382499 has 2 divisors, whose sum is σ = 21382500. Its totient is φ = 21382498.

The previous prime is 21382463. The next prime is 21382511. The reversal of 21382499 is 99428312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21382499 is a prime.

It is a super-2 number, since 2×21382499² = 914422526970002, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21382409) 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, 10691249 + 10691250.

It is an arithmetic number, because the mean of its divisors is an integer number (10691250).

Almost surely, 2^21382499 is an apocalyptic number.

21382499 is a deficient number, since it is larger than the sum of its proper divisors (1).

21382499 is an equidigital number, since it uses as much as digits as its factorization.

21382499 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 38.

The square root of 21382499 is about 4624.1214300665. The cubic root of 21382499 is about 277.5574060822.

The spelling of 21382499 in words is "twenty-one million, three hundred eighty-two thousand, four hundred ninety-nine".