16821828 has 72 divisors (see below), whose sum is σ = 44525208. Its totient is φ = 5349888.

The previous prime is 16821793. The next prime is 16821839. The reversal of 16821828 is 82812861.

It can be written as a sum of positive squares in 4 ways, for example, as 10227204 + 6594624 = 3198^2 + 2568^2 .

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 16821792 and 16821801.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 97150 + ... + 97322.

Almost surely, 2^16821828 is an apocalyptic number.

16821828 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16821828, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22262604).

16821828 is an abundant number, since it is smaller than the sum of its proper divisors (27703380).

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

16821828 is a wasteful number, since it uses less digits than its factorization.

16821828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293 (or 288 counting only the distinct ones).

The product of its digits is 12288, while the sum is 36.

The square root of 16821828 is about 4101.4421853782. The cubic root of 16821828 is about 256.2267075398.

The spelling of 16821828 in words is "sixteen million, eight hundred twenty-one thousand, eight hundred twenty-eight".