28390920 has 64 divisors (see below), whose sum is σ = 86037120. Its totient is φ = 7494144.

The previous prime is 28390919. The next prime is 28390927. The reversal of 28390920 is 2909382.

It is not an unprimeable number, because it can be changed into a prime (28390927) 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, 11212 + ... + 13508.

It is an arithmetic number, because the mean of its divisors is an integer number (1344330).

Almost surely, 2^28390920 is an apocalyptic number.

28390920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28390920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43018560).

28390920 is an abundant number, since it is smaller than the sum of its proper divisors (57646200).

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

28390920 is a wasteful number, since it uses less digits than its factorization.

28390920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2414 (or 2410 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 28390920 is about 5328.3130538661. The cubic root of 28390920 is about 305.0655417688.

The spelling of 28390920 in words is "twenty-eight million, three hundred ninety thousand, nine hundred twenty".