391671871 has 8 divisors (see below), whose sum is σ = 412476800. Its totient is φ = 370886040.

The previous prime is 391671851. The next prime is 391671901. The reversal of 391671871 is 178176193.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 391671871 - 2⁷ = 391671743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391671851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59956 + ... + 66166.

It is an arithmetic number, because the mean of its divisors is an integer number (51559600).

Almost surely, 2^391671871 is an apocalyptic number.

391671871 is a deficient number, since it is larger than the sum of its proper divisors (20804929).

391671871 is a wasteful number, since it uses less digits than its factorization.

391671871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9549.

The product of its digits is 63504, while the sum is 43.

The square root of 391671871 is about 19790.7016298059. The cubic root of 391671871 is about 731.6568801837.

The spelling of 391671871 in words is "three hundred ninety-one million, six hundred seventy-one thousand, eight hundred seventy-one".