28638875 has 16 divisors (see below), whose sum is σ = 35953632. Its totient is φ = 22775200.

The previous prime is 28638847. The next prime is 28638889. The reversal of 28638875 is 57883682.

It is not a de Polignac number, because 28638875 - 2¹⁸ = 28376731 is a prime.

It is a super-2 number, since 2×28638875² = 1640370322531250, which contains 22 as substring.

It is a Duffinian number.

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 15 ways as a sum of consecutive naturals, for example, 24044 + ... + 25206.

It is an arithmetic number, because the mean of its divisors is an integer number (2247102).

Almost surely, 2^28638875 is an apocalyptic number.

28638875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28638875 is a deficient number, since it is larger than the sum of its proper divisors (7314757).

28638875 is a wasteful number, since it uses less digits than its factorization.

28638875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1375 (or 1365 counting only the distinct ones).

The product of its digits is 645120, while the sum is 47.

The square root of 28638875 is about 5351.5301550117. The cubic root of 28638875 is about 305.9510758071.

The spelling of 28638875 in words is "twenty-eight million, six hundred thirty-eight thousand, eight hundred seventy-five".