21322439 has 2 divisors, whose sum is σ = 21322440. Its totient is φ = 21322438.

The previous prime is 21322417. The next prime is 21322463. The reversal of 21322439 is 93422312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21322439 - 2¹² = 21318343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21322139) 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, 10661219 + 10661220.

It is an arithmetic number, because the mean of its divisors is an integer number (10661220).

Almost surely, 2^21322439 is an apocalyptic number.

21322439 is a deficient number, since it is larger than the sum of its proper divisors (1).

21322439 is an equidigital number, since it uses as much as digits as its factorization.

21322439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 26.

The square root of 21322439 is about 4617.6226567358. The cubic root of 21322439 is about 277.2972910213.

The spelling of 21322439 in words is "twenty-one million, three hundred twenty-two thousand, four hundred thirty-nine".