21908937 has 8 divisors (see below), whose sum is σ = 30930336. Its totient is φ = 13746752.

The previous prime is 21908917. The next prime is 21908947. The reversal of 21908937 is 73980912.

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 21908937 - 2⁸ = 21908681 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21908895 and 21908904.

It is not an unprimeable number, because it can be changed into a prime (21908917) 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 7 ways as a sum of consecutive naturals, for example, 214743 + ... + 214844.

It is an arithmetic number, because the mean of its divisors is an integer number (3866292).

Almost surely, 2^21908937 is an apocalyptic number.

It is an amenable number.

21908937 is a deficient number, since it is larger than the sum of its proper divisors (9021399).

21908937 is a wasteful number, since it uses less digits than its factorization.

21908937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429607.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 21908937 is about 4680.6983453327. The cubic root of 21908937 is about 279.8167891604.

The spelling of 21908937 in words is "twenty-one million, nine hundred eight thousand, nine hundred thirty-seven".