21133998 has 24 divisors (see below), whose sum is σ = 46222488. Its totient is φ = 6978192.

The previous prime is 21133979. The next prime is 21134021. The reversal of 21133998 is 89933112.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 3561 + ... + 7412.

It is an arithmetic number, because the mean of its divisors is an integer number (1925937).

Almost surely, 2^21133998 is an apocalyptic number.

21133998 is an abundant number, since it is smaller than the sum of its proper divisors (25088490).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21133998 is a wasteful number, since it uses less digits than its factorization.

21133998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11088 (or 11085 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 21133998 is about 4597.1728268578. The cubic root of 21133998 is about 276.4779839614.

The spelling of 21133998 in words is "twenty-one million, one hundred thirty-three thousand, nine hundred ninety-eight".