28313181 has 12 divisors (see below), whose sum is σ = 44042908. Its totient is φ = 17423424.

The previous prime is 28313179. The next prime is 28313191. The reversal of 28313181 is 18131382.

It can be written as a sum of positive squares in 2 ways, for example, as 1625625 + 26687556 = 1275^2 + 5166^2 .

It is not a de Polignac number, because 28313181 - 2¹ = 28313179 is a prime.

It is a super-2 number, since 2×28313181² = 1603272436677522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28313111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 120880 + ... + 121113.

Almost surely, 2^28313181 is an apocalyptic number.

It is an amenable number.

28313181 is a deficient number, since it is larger than the sum of its proper divisors (15729727).

28313181 is a wasteful number, since it uses less digits than its factorization.

28313181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242012 (or 242009 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 28313181 is about 5321.0131554057. The cubic root of 28313181 is about 304.7868473978.

The spelling of 28313181 in words is "twenty-eight million, three hundred thirteen thousand, one hundred eighty-one".