28775181 has 4 divisors (see below), whose sum is σ = 38366912. Its totient is φ = 19183452.

The previous prime is 28775179. The next prime is 28775207. The reversal of 28775181 is 18157782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28775181 - 2¹ = 28775179 is a prime.

It is a super-2 number, since 2×28775181² = 1656022083165522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28775141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4795861 + ... + 4795866.

It is an arithmetic number, because the mean of its divisors is an integer number (9591728).

Almost surely, 2^28775181 is an apocalyptic number.

It is an amenable number.

28775181 is a deficient number, since it is larger than the sum of its proper divisors (9591731).

28775181 is an equidigital number, since it uses as much as digits as its factorization.

28775181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9591730.

The product of its digits is 31360, while the sum is 39.

The square root of 28775181 is about 5364.2502738034. The cubic root of 28775181 is about 306.4356965696.

The spelling of 28775181 in words is "twenty-eight million, seven hundred seventy-five thousand, one hundred eighty-one".