21422439 has 6 divisors (see below), whose sum is σ = 30943536. Its totient is φ = 14281620.

The previous prime is 21422419. The next prime is 21422449. The reversal of 21422439 is 93422412.

It is not a de Polignac number, because 21422439 - 2¹⁵ = 21389671 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21422419) 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 in 5 ways as a sum of consecutive naturals, for example, 1190127 + ... + 1190144.

It is an arithmetic number, because the mean of its divisors is an integer number (5157256).

Almost surely, 2^21422439 is an apocalyptic number.

21422439 is a deficient number, since it is larger than the sum of its proper divisors (9521097).

21422439 is a wasteful number, since it uses less digits than its factorization.

21422439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2380277 (or 2380274 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 21422439 is about 4628.4380734758. The cubic root of 21422439 is about 277.7301134869.

Subtracting from 21422439 its sum of digits (27), we obtain a palindrome (21422412).

The spelling of 21422439 in words is "twenty-one million, four hundred twenty-two thousand, four hundred thirty-nine".