28039240 has 32 divisors (see below), whose sum is σ = 63581760. Its totient is φ = 11128000.

The previous prime is 28039237. The next prime is 28039247. The reversal of 28039240 is 4293082.

It is a junction number, because it is equal to n+sod(n) for n = 28039199 and 28039208.

It is not an unprimeable number, because it can be changed into a prime (28039247) 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, 2565 + ... + 7915.

It is an arithmetic number, because the mean of its divisors is an integer number (1986930).

Almost surely, 2^28039240 is an apocalyptic number.

28039240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28039240 is an abundant number, since it is smaller than the sum of its proper divisors (35542520).

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

28039240 is a wasteful number, since it uses less digits than its factorization.

28039240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5493 (or 5489 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 28039240 is about 5295.2091554536. The cubic root of 28039240 is about 303.8006830588.

The spelling of 28039240 in words is "twenty-eight million, thirty-nine thousand, two hundred forty".