21438359 has 2 divisors, whose sum is σ = 21438360. Its totient is φ = 21438358.

The previous prime is 21438353. The next prime is 21438401. The reversal of 21438359 is 95383412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21438359 - 2⁸ = 21438103 is a prime.

It is a super-2 number, since 2×21438359² = 919206473225762, which contains 22 as substring.

It is a zygodrome in base 3.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21438353) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10719179 + 10719180.

It is an arithmetic number, because the mean of its divisors is an integer number (10719180).

Almost surely, 2^21438359 is an apocalyptic number.

21438359 is a deficient number, since it is larger than the sum of its proper divisors (1).

21438359 is an equidigital number, since it uses as much as digits as its factorization.

21438359 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25920, while the sum is 35.

The square root of 21438359 is about 4630.1575567145. The cubic root of 21438359 is about 277.7988944599.

The spelling of 21438359 in words is "twenty-one million, four hundred thirty-eight thousand, three hundred fifty-nine".