391393197 has 54 divisors (see below), whose sum is σ = 639950766. Its totient is φ = 229137120.

The previous prime is 391393187. The next prime is 391393199. The reversal of 391393197 is 791393193.

It can be written as a sum of positive squares in only one way, i.e., 270964521 + 120428676 = 16461^2 + 10974^2 .

It is not a de Polignac number, because 391393197 - 2⁷ = 391393069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391393199) 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 in 53 ways as a sum of consecutive naturals, for example, 6633754 + ... + 6633812.

Almost surely, 2^391393197 is an apocalyptic number.

It is an amenable number.

391393197 is a deficient number, since it is larger than the sum of its proper divisors (248557569).

391393197 is a wasteful number, since it uses less digits than its factorization.

391393197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199 (or 106 counting only the distinct ones).

The product of its digits is 137781, while the sum is 45.

The square root of 391393197 is about 19783.6598484709. The cubic root of 391393197 is about 731.4833147238.

The spelling of 391393197 in words is "three hundred ninety-one million, three hundred ninety-three thousand, one hundred ninety-seven".