28387920 has 80 divisors (see below), whose sum is σ = 96011712. Its totient is φ = 6881280.

The previous prime is 28387903. The next prime is 28387921. The reversal of 28387920 is 2978382.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28387921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2737 + ... + 8016.

Almost surely, 2^28387920 is an apocalyptic number.

28387920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28387920 is an abundant number, since it is smaller than the sum of its proper divisors (67623792).

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

28387920 is a wasteful number, since it uses less digits than its factorization.

28387920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10780 (or 10774 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 28387920 is about 5328.0315314382. The cubic root of 28387920 is about 305.0547962105.

The spelling of 28387920 in words is "twenty-eight million, three hundred eighty-seven thousand, nine hundred twenty".