21359439 has 12 divisors (see below), whose sum is σ = 32476600. Its totient is φ = 13490064.

The previous prime is 21359431. The next prime is 21359441. The reversal of 21359439 is 93495312.

It is a happy number.

21359439 is a `hidden beast` number, since 213 + 5 + 9 + 439 = 666.

It is not a de Polignac number, because 21359439 - 2³ = 21359431 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21359431) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 62284 + ... + 62625.

Almost surely, 2^21359439 is an apocalyptic number.

21359439 is a deficient number, since it is larger than the sum of its proper divisors (11117161).

21359439 is a wasteful number, since it uses less digits than its factorization.

21359439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124934 (or 124931 counting only the distinct ones).

The product of its digits is 29160, while the sum is 36.

The square root of 21359439 is about 4621.6273108073. The cubic root of 21359439 is about 277.4575927405.

The spelling of 21359439 in words is "twenty-one million, three hundred fifty-nine thousand, four hundred thirty-nine".