28409880 has 32 divisors (see below), whose sum is σ = 85230000. Its totient is φ = 7575936.

The previous prime is 28409867. The next prime is 28409881. The reversal of 28409880 is 8890482.

It is a happy number.

It is a super-3 number, since 3×28409880³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28409881) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 118255 + ... + 118494.

Almost surely, 2^28409880 is an apocalyptic number.

28409880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28409880 is an abundant number, since it is smaller than the sum of its proper divisors (56820120).

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

28409880 is a wasteful number, since it uses less digits than its factorization.

28409880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236763 (or 236759 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 39.

The square root of 28409880 is about 5330.0919316650. The cubic root of 28409880 is about 305.1334361940.

It can be divided in two parts, 2840 and 9880, that added together give a triangular number (12720 = T₁₅₉).

The spelling of 28409880 in words is "twenty-eight million, four hundred nine thousand, eight hundred eighty".