21106828 has 6 divisors (see below), whose sum is σ = 36936956. Its totient is φ = 10553412.

The previous prime is 21106819. The next prime is 21106831. The reversal of 21106828 is 82860112.

It is a junction number, because it is equal to n+sod(n) for n = 21106796 and 21106805.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2638350 + ... + 2638357.

Almost surely, 2^21106828 is an apocalyptic number.

It is an amenable number.

21106828 is a deficient number, since it is larger than the sum of its proper divisors (15830128).

21106828 is a wasteful number, since it uses less digits than its factorization.

21106828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5276711 (or 5276709 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 21106828 is about 4594.2167994121. The cubic root of 21106828 is about 276.3594525436.

The spelling of 21106828 in words is "twenty-one million, one hundred six thousand, eight hundred twenty-eight".