21293439 has 16 divisors (see below), whose sum is σ = 29145312. Its totient is φ = 13822848.

The previous prime is 21293431. The next prime is 21293483. The reversal of 21293439 is 93439212.

It is not a de Polignac number, because 21293439 - 2³ = 21293431 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21293431) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24537 + ... + 25389.

It is an arithmetic number, because the mean of its divisors is an integer number (1821582).

Almost surely, 2^21293439 is an apocalyptic number.

21293439 is a deficient number, since it is larger than the sum of its proper divisors (7851873).

21293439 is a wasteful number, since it uses less digits than its factorization.

21293439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1066.

The product of its digits is 11664, while the sum is 33.

The square root of 21293439 is about 4614.4814443229. The cubic root of 21293439 is about 277.1715194508.

The spelling of 21293439 in words is "twenty-one million, two hundred ninety-three thousand, four hundred thirty-nine".