21036828 has 12 divisors (see below), whose sum is σ = 49085960. Its totient is φ = 7012272.

The previous prime is 21036811. The next prime is 21036833. The reversal of 21036828 is 82863012.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 21036795 and 21036804.

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 3 ways as a sum of consecutive naturals, for example, 876523 + ... + 876546.

Almost surely, 2^21036828 is an apocalyptic number.

It is an amenable number.

21036828 is an abundant number, since it is smaller than the sum of its proper divisors (28049132).

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

21036828 is a wasteful number, since it uses less digits than its factorization.

21036828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1753076 (or 1753074 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 21036828 is about 4586.5921990079. The cubic root of 21036828 is about 276.0536022756.

The spelling of 21036828 in words is "twenty-one million, thirty-six thousand, eight hundred twenty-eight".