21956339 has 4 divisors (see below), whose sum is σ = 22664640. Its totient is φ = 21248040.

The previous prime is 21956323. The next prime is 21956351. The reversal of 21956339 is 93365912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21956339 - 2⁴ = 21956323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21956399) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 354104 + ... + 354165.

It is an arithmetic number, because the mean of its divisors is an integer number (5666160).

Almost surely, 2^21956339 is an apocalyptic number.

21956339 is a deficient number, since it is larger than the sum of its proper divisors (708301).

21956339 is an equidigital number, since it uses as much as digits as its factorization.

21956339 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708300.

The product of its digits is 43740, while the sum is 38.

The square root of 21956339 is about 4685.7591700812. The cubic root of 21956339 is about 280.0184469139.

The spelling of 21956339 in words is "twenty-one million, nine hundred fifty-six thousand, three hundred thirty-nine".