391408197 has 4 divisors (see below), whose sum is σ = 521877600. Its totient is φ = 260938796.

The previous prime is 391408133. The next prime is 391408211. The reversal of 391408197 is 791804193.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 391408197 - 2⁶ = 391408133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391408097) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65234697 + ... + 65234702.

It is an arithmetic number, because the mean of its divisors is an integer number (130469400).

Almost surely, 2^391408197 is an apocalyptic number.

It is an amenable number.

391408197 is a deficient number, since it is larger than the sum of its proper divisors (130469403).

391408197 is a wasteful number, since it uses less digits than its factorization.

391408197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130469402.

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 391408197 is about 19784.0389455743. The cubic root of 391408197 is about 731.4926592139.

The spelling of 391408197 in words is "three hundred ninety-one million, four hundred eight thousand, one hundred ninety-seven".