28791640 has 16 divisors (see below), whose sum is σ = 64781280. Its totient is φ = 11516640.

The previous prime is 28791619. The next prime is 28791643. The reversal of 28791640 is 4619782.

It is a self number, because there is not a number n which added to its sum of digits gives 28791640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28791643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 359856 + ... + 359935.

It is an arithmetic number, because the mean of its divisors is an integer number (4048830).

Almost surely, 2^28791640 is an apocalyptic number.

28791640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28791640 is an abundant number, since it is smaller than the sum of its proper divisors (35989640).

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

28791640 is a wasteful number, since it uses less digits than its factorization.

28791640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 719802 (or 719798 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 28791640 is about 5365.7841924550. The cubic root of 28791640 is about 306.4941110740.

The spelling of 28791640 in words is "twenty-eight million, seven hundred ninety-one thousand, six hundred forty".