28178138 has 8 divisors (see below), whose sum is σ = 42403188. Its totient is φ = 14043744.

The previous prime is 28178119. The next prime is 28178149. The reversal of 28178138 is 83187182.

It can be written as a sum of positive squares in 2 ways, for example, as 17530969 + 10647169 = 4187^2 + 3263^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×28178138² = 1588014922294088, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21881 + ... + 23132.

Almost surely, 2^28178138 is an apocalyptic number.

28178138 is a deficient number, since it is larger than the sum of its proper divisors (14225050).

28178138 is a wasteful number, since it uses less digits than its factorization.

28178138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45328.

The product of its digits is 21504, while the sum is 38.

The square root of 28178138 is about 5308.3083934527. The cubic root of 28178138 is about 304.3015028717.

The spelling of 28178138 in words is "twenty-eight million, one hundred seventy-eight thousand, one hundred thirty-eight".