21908799 has 40 divisors (see below), whose sum is σ = 36334848. Its totient is φ = 13044240.

The previous prime is 21908797. The next prime is 21908827. The reversal of 21908799 is 99780912.

It is not a de Polignac number, because 21908799 - 2¹ = 21908797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21908791) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 59514 + ... + 59880.

Almost surely, 2^21908799 is an apocalyptic number.

21908799 is a deficient number, since it is larger than the sum of its proper divisors (14426049).

21908799 is a wasteful number, since it uses less digits than its factorization.

21908799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 457 (or 448 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The square root of 21908799 is about 4680.6836039194. The cubic root of 21908799 is about 279.8162016559.

The spelling of 21908799 in words is "twenty-one million, nine hundred eight thousand, seven hundred ninety-nine".