21998908 has 6 divisors (see below), whose sum is σ = 38498096. Its totient is φ = 10999452.

The previous prime is 21998897. The next prime is 21998909. The reversal of 21998908 is 80989912.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21998909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2749860 + ... + 2749867.

Almost surely, 2^21998908 is an apocalyptic number.

It is an amenable number.

21998908 is a deficient number, since it is larger than the sum of its proper divisors (16499188).

21998908 is a wasteful number, since it uses less digits than its factorization.

21998908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5499731 (or 5499729 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 46.

The square root of 21998908 is about 4690.2993507878. The cubic root of 21998908 is about 280.1992968874.

The spelling of 21998908 in words is "twenty-one million, nine hundred ninety-eight thousand, nine hundred eight".