28999980 has 72 divisors (see below), whose sum is σ = 89212032. Its totient is φ = 7623936.

The previous prime is 28999979. The next prime is 28999991. The reversal of 28999980 is 8999982.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12037 + ... + 14243.

It is an arithmetic number, because the mean of its divisors is an integer number (1239056).

Almost surely, 2^28999980 is an apocalyptic number.

28999980 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 28999980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44606016).

28999980 is an abundant number, since it is smaller than the sum of its proper divisors (60212052).

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

28999980 is a wasteful number, since it uses less digits than its factorization.

28999980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2295 (or 2290 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 54.

The square root of 28999980 is about 5385.1629501808. The cubic root of 28999980 is about 307.2316119406.

The spelling of 28999980 in words is "twenty-eight million, nine hundred ninety-nine thousand, nine hundred eighty".