21874239 has 16 divisors (see below), whose sum is σ = 32486400. Its totient is φ = 14546808.

The previous prime is 21874199. The next prime is 21874241. The reversal of 21874239 is 93247812.

It is not a de Polignac number, because 21874239 - 2⁹ = 21873727 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21874939) 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, 14482 + ... + 15920.

It is an arithmetic number, because the mean of its divisors is an integer number (2030400).

Almost surely, 2^21874239 is an apocalyptic number.

21874239 is a deficient number, since it is larger than the sum of its proper divisors (10612161).

21874239 is a wasteful number, since it uses less digits than its factorization.

21874239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2011 (or 2005 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21874239 is about 4676.9903784378. The cubic root of 21874239 is about 279.6689923502.

The spelling of 21874239 in words is "twenty-one million, eight hundred seventy-four thousand, two hundred thirty-nine".