21150828 has 96 divisors (see below), whose sum is σ = 57881600. Its totient is φ = 6671808.

The previous prime is 21150827. The next prime is 21150841. The reversal of 21150828 is 82805112.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21150821) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 267693 + ... + 267771.

Almost surely, 2^21150828 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21150828, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28940800).

21150828 is an abundant number, since it is smaller than the sum of its proper divisors (36730772).

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

21150828 is a wasteful number, since it uses less digits than its factorization.

21150828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 21150828 is about 4599.0029354198. The cubic root of 21150828 is about 276.5513553107.

Subtracting from 21150828 its sum of digits (27), we obtain a square (21150801 = 4599²).

The spelling of 21150828 in words is "twenty-one million, one hundred fifty thousand, eight hundred twenty-eight".