21030828 has 48 divisors (see below), whose sum is σ = 60399360. Its totient is φ = 5546304.

The previous prime is 21030797. The next prime is 21030857. The reversal of 21030828 is 82803012.

It is a junction number, because it is equal to n+sod(n) for n = 21030798 and 21030807.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8538 + ... + 10721.

It is an arithmetic number, because the mean of its divisors is an integer number (1258320).

Almost surely, 2^21030828 is an apocalyptic number.

21030828 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21030828 is an abundant number, since it is smaller than the sum of its proper divisors (39368532).

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

21030828 is a wasteful number, since it uses less digits than its factorization.

21030828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19286 (or 19284 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21030828 is about 4585.9380719761. The cubic root of 21030828 is about 276.0273549867.

The spelling of 21030828 in words is "twenty-one million, thirty thousand, eight hundred twenty-eight".