28039140 has 36 divisors (see below), whose sum is σ = 85052604. Its totient is φ = 7477056.

The previous prime is 28039129. The next prime is 28039153. The reversal of 28039140 is 4193082.

It can be written as a sum of positive squares in 2 ways, for example, as 8538084 + 19501056 = 2922^2 + 4416^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 77707 + ... + 78066.

Almost surely, 2^28039140 is an apocalyptic number.

28039140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28039140 is an abundant number, since it is smaller than the sum of its proper divisors (57013464).

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

28039140 is a wasteful number, since it uses less digits than its factorization.

28039140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155788 (or 155783 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 28039140 is about 5295.1997129476. The cubic root of 28039140 is about 303.8003218970.

The spelling of 28039140 in words is "twenty-eight million, thirty-nine thousand, one hundred forty".