28931291 has 2 divisors, whose sum is σ = 28931292. Its totient is φ = 28931290.

The previous prime is 28931267. The next prime is 28931311. The reversal of 28931291 is 19213982.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28931291 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28931251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14465645 + 14465646.

It is an arithmetic number, because the mean of its divisors is an integer number (14465646).

Almost surely, 2^28931291 is an apocalyptic number.

28931291 is a deficient number, since it is larger than the sum of its proper divisors (1).

28931291 is an equidigital number, since it uses as much as digits as its factorization.

28931291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 35.

The square root of 28931291 is about 5378.7815534747. The cubic root of 28931291 is about 306.9888518200.

The spelling of 28931291 in words is "twenty-eight million, nine hundred thirty-one thousand, two hundred ninety-one".