21856339 has 8 divisors (see below), whose sum is σ = 23182848. Its totient is φ = 20534400.

The previous prime is 21856337. The next prime is 21856349. The reversal of 21856339 is 93365812.

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 21856339 - 2¹ = 21856337 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21856298 and 21856307.

It is not an unprimeable number, because it can be changed into a prime (21856337) 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, 18414 + ... + 19564.

It is an arithmetic number, because the mean of its divisors is an integer number (2897856).

Almost surely, 2^21856339 is an apocalyptic number.

21856339 is a deficient number, since it is larger than the sum of its proper divisors (1326509).

21856339 is a wasteful number, since it uses less digits than its factorization.

21856339 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2285.

The product of its digits is 38880, while the sum is 37.

The square root of 21856339 is about 4675.0763630127. The cubic root of 21856339 is about 279.5926858313.

The spelling of 21856339 in words is "twenty-one million, eight hundred fifty-six thousand, three hundred thirty-nine".