28113181 has 2 divisors, whose sum is σ = 28113182. Its totient is φ = 28113180.

The previous prime is 28113149. The next prime is 28113193. The reversal of 28113181 is 18131182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19316025 + 8797156 = 4395^2 + 2966^2 .

It is a cyclic number.

It is not a de Polignac number, because 28113181 - 2⁵ = 28113149 is a prime.

It is a super-2 number, since 2×28113181² = 1580701891877522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28113781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14056590 + 14056591.

It is an arithmetic number, because the mean of its divisors is an integer number (14056591).

Almost surely, 2^28113181 is an apocalyptic number.

It is an amenable number.

28113181 is a deficient number, since it is larger than the sum of its proper divisors (1).

28113181 is an equidigital number, since it uses as much as digits as its factorization.

28113181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 25.

The square root of 28113181 is about 5302.1864358017. The cubic root of 28113181 is about 304.0674949684.

The spelling of 28113181 in words is "twenty-eight million, one hundred thirteen thousand, one hundred eighty-one".