28666820 has 96 divisors (see below), whose sum is σ = 78086400. Its totient is φ = 8584704.

The previous prime is 28666817. The next prime is 28666837. The reversal of 28666820 is 2866682.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34166 + ... + 34994.

It is an arithmetic number, because the mean of its divisors is an integer number (813400).

Almost surely, 2^28666820 is an apocalyptic number.

28666820 is a gapful number since it is divisible by the number (20) 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 28666820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39043200).

28666820 is an abundant number, since it is smaller than the sum of its proper divisors (49419580).

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

28666820 is a wasteful number, since it uses less digits than its factorization.

28666820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 877 (or 875 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 38.

The square root of 28666820 is about 5354.1404538917. The cubic root of 28666820 is about 306.0505562445.

The spelling of 28666820 in words is "twenty-eight million, six hundred sixty-six thousand, eight hundred twenty".