28400080 has 40 divisors (see below), whose sum is σ = 66495744. Its totient is φ = 11280000.

The previous prime is 28400069. The next prime is 28400093. The reversal of 28400080 is 8000482.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10905 + ... + 13255.

Almost surely, 2^28400080 is an apocalyptic number.

28400080 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 28400080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33247872).

28400080 is an abundant number, since it is smaller than the sum of its proper divisors (38095664).

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

28400080 is a wasteful number, since it uses less digits than its factorization.

28400080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2515 (or 2509 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 22.

The square root of 28400080 is about 5329.1725436507. The cubic root of 28400080 is about 305.0983468568.

The spelling of 28400080 in words is "twenty-eight million, four hundred thousand, eighty".