28400238 has 24 divisors (see below), whose sum is σ = 63198408. Its totient is φ = 9210672.

The previous prime is 28400221. The next prime is 28400243. The reversal of 28400238 is 83200482.

28400238 is a `hidden beast` number, since 28 + 400 + 238 = 666.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20656 + ... + 21987.

It is an arithmetic number, because the mean of its divisors is an integer number (2633267).

Almost surely, 2^28400238 is an apocalyptic number.

28400238 is an abundant number, since it is smaller than the sum of its proper divisors (34798170).

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

28400238 is a wasteful number, since it uses less digits than its factorization.

28400238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42688 (or 42685 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 28400238 is about 5329.1873676950. The cubic root of 28400238 is about 305.0989126469.

The spelling of 28400238 in words is "twenty-eight million, four hundred thousand, two hundred thirty-eight".