28028775 has 12 divisors (see below), whose sum is σ = 46341032. Its totient is φ = 14948640.

The previous prime is 28028753. The next prime is 28028807. The reversal of 28028775 is 57782082.

It is not a de Polignac number, because 28028775 - 2¹² = 28024679 is a prime.

It is a super-2 number, since 2×28028775² = 1571224456001250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent 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 11 ways as a sum of consecutive naturals, for example, 186784 + ... + 186933.

Almost surely, 2^28028775 is an apocalyptic number.

28028775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28028775 is a deficient number, since it is larger than the sum of its proper divisors (18312257).

28028775 is a wasteful number, since it uses less digits than its factorization.

28028775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 373730 (or 373725 counting only the distinct ones).

The product of its (nonzero) digits is 62720, while the sum is 39.

The square root of 28028775 is about 5294.2209058557. The cubic root of 28028775 is about 303.7628828216.

The spelling of 28028775 in words is "twenty-eight million, twenty-eight thousand, seven hundred seventy-five".