21375239 has 8 divisors (see below), whose sum is σ = 22906800. Its totient is φ = 19874176.

The previous prime is 21375223. The next prime is 21375241. The reversal of 21375239 is 93257312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21375239 - 2⁴ = 21375223 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 (21375439) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6164 + ... + 8985.

It is an arithmetic number, because the mean of its divisors is an integer number (2863350).

Almost surely, 2^21375239 is an apocalyptic number.

21375239 is a deficient number, since it is larger than the sum of its proper divisors (1531561).

21375239 is a wasteful number, since it uses less digits than its factorization.

21375239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15249.

The product of its digits is 11340, while the sum is 32.

The square root of 21375239 is about 4623.3363494342. The cubic root of 21375239 is about 277.5259895037.

The spelling of 21375239 in words is "twenty-one million, three hundred seventy-five thousand, two hundred thirty-nine".