28667640 has 32 divisors (see below), whose sum is σ = 86003280. Its totient is φ = 7644672.

The previous prime is 28667629. The next prime is 28667663. The reversal of 28667640 is 4676682.

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, 119329 + ... + 119568.

Almost surely, 2^28667640 is an apocalyptic number.

28667640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28667640 is an abundant number, since it is smaller than the sum of its proper divisors (57335640).

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

28667640 is a wasteful number, since it uses less digits than its factorization.

28667640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238911 (or 238907 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 39.

The square root of 28667640 is about 5354.2170295945. The cubic root of 28667640 is about 306.0534743575.

The spelling of 28667640 in words is "twenty-eight million, six hundred sixty-seven thousand, six hundred forty".