28109131 has 2 divisors, whose sum is σ = 28109132. Its totient is φ = 28109130.

The previous prime is 28109117. The next prime is 28109141. The reversal of 28109131 is 13190182.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28109131 - 2²³ = 19720523 is a prime.

It is a super-2 number, since 2×28109131² = 1580246491150322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28109096 and 28109105.

It is not a weakly prime, because it can be changed into another prime (28109111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14054565 + 14054566.

It is an arithmetic number, because the mean of its divisors is an integer number (14054566).

Almost surely, 2^28109131 is an apocalyptic number.

28109131 is a deficient number, since it is larger than the sum of its proper divisors (1).

28109131 is an equidigital number, since it uses as much as digits as its factorization.

28109131 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 28109131 is about 5301.8045041288. The cubic root of 28109131 is about 304.0528928915.

The spelling of 28109131 in words is "twenty-eight million, one hundred nine thousand, one hundred thirty-one".