21108982 has 4 divisors (see below), whose sum is σ = 31663476. Its totient is φ = 10554490.

The previous prime is 21108977. The next prime is 21109007. The reversal of 21108982 is 28980112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5277244 + ... + 5277247.

It is an arithmetic number, because the mean of its divisors is an integer number (7915869).

Almost surely, 2^21108982 is an apocalyptic number.

21108982 is a deficient number, since it is larger than the sum of its proper divisors (10554494).

21108982 is a wasteful number, since it uses less digits than its factorization.

21108982 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10554493.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 21108982 is about 4594.4512185897. The cubic root of 21108982 is about 276.3688532616.

The spelling of 21108982 in words is "twenty-one million, one hundred eight thousand, nine hundred eighty-two".