391129221 has 12 divisors (see below), whose sum is σ = 606649632. Its totient is φ = 223502328.

The previous prime is 391129199. The next prime is 391129261. The reversal of 391129221 is 122921193.

It is not a de Polignac number, because 391129221 - 2⁷ = 391129093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391129261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1330225 + ... + 1330518.

It is an arithmetic number, because the mean of its divisors is an integer number (50554136).

Almost surely, 2^391129221 is an apocalyptic number.

It is an amenable number.

391129221 is a deficient number, since it is larger than the sum of its proper divisors (215520411).

391129221 is a wasteful number, since it uses less digits than its factorization.

391129221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2660760 (or 2660753 counting only the distinct ones).

The product of its digits is 1944, while the sum is 30.

The square root of 391129221 is about 19776.9871567941. The cubic root of 391129221 is about 731.3188275635.

The spelling of 391129221 in words is "three hundred ninety-one million, one hundred twenty-nine thousand, two hundred twenty-one".