21908933 has 4 divisors (see below), whose sum is σ = 22236000. Its totient is φ = 21581868.

The previous prime is 21908917. The next prime is 21908947. The reversal of 21908933 is 33980912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21908933 - 2⁴ = 21908917 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21908893 and 21908902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21908233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163433 + ... + 163566.

It is an arithmetic number, because the mean of its divisors is an integer number (5559000).

Almost surely, 2^21908933 is an apocalyptic number.

It is an amenable number.

21908933 is a deficient number, since it is larger than the sum of its proper divisors (327067).

21908933 is an equidigital number, since it uses as much as digits as its factorization.

21908933 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327066.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 21908933 is about 4680.6979180460. The cubic root of 21908933 is about 279.8167721313.

The spelling of 21908933 in words is "twenty-one million, nine hundred eight thousand, nine hundred thirty-three".