28131111 has 8 divisors (see below), whose sum is σ = 41675760. Its totient is φ = 18754056.

The previous prime is 28131109. The next prime is 28131113. The reversal of 28131111 is 11113182.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (28131109) and next prime (28131113).

It is not a de Polignac number, because 28131111 - 2¹ = 28131109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28131113) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 520920 + ... + 520973.

It is an arithmetic number, because the mean of its divisors is an integer number (5209470).

Almost surely, 2^28131111 is an apocalyptic number.

28131111 is a deficient number, since it is larger than the sum of its proper divisors (13544649).

28131111 is a wasteful number, since it uses less digits than its factorization.

28131111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1041902 (or 1041896 counting only the distinct ones).

The product of its digits is 48, while the sum is 18.

The square root of 28131111 is about 5303.8769782113. The cubic root of 28131111 is about 304.1321238644.

Adding to 28131111 its reverse (11113182), we get a palindrome (39244293).

The spelling of 28131111 in words is "twenty-eight million, one hundred thirty-one thousand, one hundred eleven".