21857339 has 8 divisors (see below), whose sum is σ = 25125600. Its totient is φ = 18625536.

The previous prime is 21857293. The next prime is 21857357. The reversal of 21857339 is 93375812.

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 21857339 - 2⁸ = 21857083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21857389) 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, 7814 + ... + 10235.

It is an arithmetic number, because the mean of its divisors is an integer number (3140700).

Almost surely, 2^21857339 is an apocalyptic number.

21857339 is a deficient number, since it is larger than the sum of its proper divisors (3268261).

21857339 is a wasteful number, since it uses less digits than its factorization.

21857339 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18229.

The product of its digits is 45360, while the sum is 38.

The square root of 21857339 is about 4675.1833119141. The cubic root of 21857339 is about 279.5969498638.

The spelling of 21857339 in words is "twenty-one million, eight hundred fifty-seven thousand, three hundred thirty-nine".