28390940 has 24 divisors (see below), whose sum is σ = 62759760. Its totient is φ = 10758528.

The previous prime is 28390939. The next prime is 28390979. The reversal of 28390940 is 4909382.

It is a self number, because there is not a number n which added to its sum of digits gives 28390940.

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, 36977 + ... + 37736.

It is an arithmetic number, because the mean of its divisors is an integer number (2614990).

Almost surely, 2^28390940 is an apocalyptic number.

28390940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28390940 is an abundant number, since it is smaller than the sum of its proper divisors (34368820).

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

28390940 is a wasteful number, since it uses less digits than its factorization.

28390940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74741 (or 74739 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 28390940 is about 5328.3149306324. The cubic root of 28390940 is about 305.0656134033.

The spelling of 28390940 in words is "twenty-eight million, three hundred ninety thousand, nine hundred forty".