28166640 has 40 divisors (see below), whose sum is σ = 87317328. Its totient is φ = 7511040.

The previous prime is 28166629. The next prime is 28166647. The reversal of 28166640 is 4666182.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28166647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58441 + ... + 58920.

Almost surely, 2^28166640 is an apocalyptic number.

28166640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28166640 is an abundant number, since it is smaller than the sum of its proper divisors (59150688).

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

28166640 is a wasteful number, since it uses less digits than its factorization.

28166640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117377 (or 117371 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 28166640 is about 5307.2252637325. The cubic root of 28166640 is about 304.2601074858.

The spelling of 28166640 in words is "twenty-eight million, one hundred sixty-six thousand, six hundred forty".