28783640 has 32 divisors (see below), whose sum is σ = 66346560. Its totient is φ = 11232000.

The previous prime is 28783637. The next prime is 28783663. The reversal of 28783640 is 4638782.

It is a junction number, because it is equal to n+sod(n) for n = 28783594 and 28783603.

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, 7136 + ... + 10415.

It is an arithmetic number, because the mean of its divisors is an integer number (2073330).

Almost surely, 2^28783640 is an apocalyptic number.

28783640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28783640 is an abundant number, since it is smaller than the sum of its proper divisors (37562920).

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

28783640 is a wasteful number, since it uses less digits than its factorization.

28783640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17603 (or 17599 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 38.

The square root of 28783640 is about 5365.0386764682. The cubic root of 28783640 is about 306.4657211198.

The spelling of 28783640 in words is "twenty-eight million, seven hundred eighty-three thousand, six hundred forty".