28117640 has 32 divisors (see below), whose sum is σ = 63855000. Its totient is φ = 11142144.

The previous prime is 28117627. The next prime is 28117699. The reversal of 28117640 is 4671182.

It can be written as a sum of positive squares in 4 ways, for example, as 28026436 + 91204 = 5294^2 + 302^2 .

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, 1136 + ... + 7584.

Almost surely, 2^28117640 is an apocalyptic number.

28117640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28117640 is an abundant number, since it is smaller than the sum of its proper divisors (35737360).

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

28117640 is a wasteful number, since it uses less digits than its factorization.

28117640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6569 (or 6565 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 28117640 is about 5302.6069060416. The cubic root of 28117640 is about 304.0835700530.

The spelling of 28117640 in words is "twenty-eight million, one hundred seventeen thousand, six hundred forty".