28403688 has 32 divisors (see below), whose sum is σ = 73301760. Its totient is φ = 9162240.

The previous prime is 28403681. The next prime is 28403699. The reversal of 28403688 is 88630482.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (28403681) 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, 18345 + ... + 19832.

It is an arithmetic number, because the mean of its divisors is an integer number (2290680).

Almost surely, 2^28403688 is an apocalyptic number.

It is an amenable number.

28403688 is an abundant number, since it is smaller than the sum of its proper divisors (44898072).

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

28403688 is a wasteful number, since it uses less digits than its factorization.

28403688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38217 (or 38213 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 39.

The square root of 28403688 is about 5329.5110469911. The cubic root of 28403688 is about 305.1112664005. Note that the first 3 decimals are identical.

The spelling of 28403688 in words is "twenty-eight million, four hundred three thousand, six hundred eighty-eight".