391224157 has 2 divisors, whose sum is σ = 391224158. Its totient is φ = 391224156.

The previous prime is 391224149. The next prime is 391224233. The reversal of 391224157 is 751422193.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 209351961 + 181872196 = 14469^2 + 13486^2 .

It is a cyclic number.

It is not a de Polignac number, because 391224157 - 2³ = 391224149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391224137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195612078 + 195612079.

It is an arithmetic number, because the mean of its divisors is an integer number (195612079).

Almost surely, 2^391224157 is an apocalyptic number.

It is an amenable number.

391224157 is a deficient number, since it is larger than the sum of its proper divisors (1).

391224157 is an equidigital number, since it uses as much as digits as its factorization.

391224157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15120, while the sum is 34.

The square root of 391224157 is about 19779.3871745310. The cubic root of 391224157 is about 731.3779920407.

The spelling of 391224157 in words is "three hundred ninety-one million, two hundred twenty-four thousand, one hundred fifty-seven".