21828828 has 24 divisors (see below), whose sum is σ = 58210432. Its totient is φ = 6236784.

The previous prime is 21828823. The next prime is 21828839. The reversal of 21828828 is 82882812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21828823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 129850 + ... + 130017.

Almost surely, 2^21828828 is an apocalyptic number.

21828828 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21828828 is an abundant number, since it is smaller than the sum of its proper divisors (36381604).

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

21828828 is a wasteful number, since it uses less digits than its factorization.

21828828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259881 (or 259879 counting only the distinct ones).

The product of its digits is 32768, while the sum is 39.

The square root of 21828828 is about 4672.1331316648. The cubic root of 21828828 is about 279.4753269887.

The spelling of 21828828 in words is "twenty-one million, eight hundred twenty-eight thousand, eight hundred twenty-eight".