28758640 has 20 divisors (see below), whose sum is σ = 66864024. Its totient is φ = 11503424.

The previous prime is 28758623. The next prime is 28758641. The reversal of 28758640 is 4685782.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 28758593 and 28758602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28758641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 179662 + ... + 179821.

Almost surely, 2^28758640 is an apocalyptic number.

28758640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28758640 is an abundant number, since it is smaller than the sum of its proper divisors (38105384).

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

28758640 is a wasteful number, since it uses less digits than its factorization.

28758640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359496 (or 359490 counting only the distinct ones).

The product of its (nonzero) digits is 107520, while the sum is 40.

The square root of 28758640 is about 5362.7082710138. The cubic root of 28758640 is about 306.3769685938.

The spelling of 28758640 in words is "twenty-eight million, seven hundred fifty-eight thousand, six hundred forty".