391274287 has 2 divisors, whose sum is σ = 391274288. Its totient is φ = 391274286.

The previous prime is 391274267. The next prime is 391274369. The reversal of 391274287 is 782472193.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 391274287 - 2¹⁹ = 390749999 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391274267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195637143 + 195637144.

It is an arithmetic number, because the mean of its divisors is an integer number (195637144).

Almost surely, 2^391274287 is an apocalyptic number.

391274287 is a deficient number, since it is larger than the sum of its proper divisors (1).

391274287 is an equidigital number, since it uses as much as digits as its factorization.

391274287 is an evil number, because the sum of its binary digits is even.

The product of its digits is 169344, while the sum is 43.

The square root of 391274287 is about 19780.6543622803. The cubic root of 391274287 is about 731.4092293865.

The spelling of 391274287 in words is "three hundred ninety-one million, two hundred seventy-four thousand, two hundred eighty-seven".