21102828 has 48 divisors (see below), whose sum is σ = 50663424. Its totient is φ = 6834240.

The previous prime is 21102821. The next prime is 21102853. The reversal of 21102828 is 82820112.

It is a junction number, because it is equal to n+sod(n) for n = 21102798 and 21102807.

It is not an unprimeable number, because it can be changed into a prime (21102821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 92851 + ... + 93077.

It is an arithmetic number, because the mean of its divisors is an integer number (1055488).

Almost surely, 2^21102828 is an apocalyptic number.

It is an amenable number.

21102828 is an abundant number, since it is smaller than the sum of its proper divisors (29560596).

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

21102828 is a wasteful number, since it uses less digits than its factorization.

21102828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422 (or 420 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 21102828 is about 4593.7814488719. The cubic root of 21102828 is about 276.3419936175.

The spelling of 21102828 in words is "twenty-one million, one hundred two thousand, eight hundred twenty-eight".