28009980 has 72 divisors (see below), whose sum is σ = 86390304. Its totient is φ = 7344000.

The previous prime is 28009973. The next prime is 28009981. The reversal of 28009980 is 8990082.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28009981) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9705 + ... + 12255.

Almost surely, 2^28009980 is an apocalyptic number.

28009980 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 28009980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43195152).

28009980 is an abundant number, since it is smaller than the sum of its proper divisors (58380324).

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

28009980 is a wasteful number, since it uses less digits than its factorization.

28009980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2627 (or 2622 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 28009980 is about 5292.4455594744. The cubic root of 28009980 is about 303.6949704710.

The spelling of 28009980 in words is "twenty-eight million, nine thousand, nine hundred eighty".