28531291 has 2 divisors, whose sum is σ = 28531292. Its totient is φ = 28531290.

The previous prime is 28531271. The next prime is 28531297. The reversal of 28531291 is 19213582.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28531291 - 2⁷ = 28531163 is a prime.

It is a super-2 number, since 2×28531291² = 1628069132253362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28531297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14265645 + 14265646.

It is an arithmetic number, because the mean of its divisors is an integer number (14265646).

Almost surely, 2^28531291 is an apocalyptic number.

28531291 is a deficient number, since it is larger than the sum of its proper divisors (1).

28531291 is an equidigital number, since it uses as much as digits as its factorization.

28531291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 31.

The square root of 28531291 is about 5341.4689927023. The cubic root of 28531291 is about 305.5674859817.

The spelling of 28531291 in words is "twenty-eight million, five hundred thirty-one thousand, two hundred ninety-one".