391657797 has 12 divisors (see below), whose sum is σ = 573696864. Its totient is φ = 257427240.

The previous prime is 391657793. The next prime is 391657807. The reversal of 391657797 is 797756193.

It is not a de Polignac number, because 391657797 - 2² = 391657793 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391657793) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 305823 + ... + 307100.

It is an arithmetic number, because the mean of its divisors is an integer number (47808072).

Almost surely, 2^391657797 is an apocalyptic number.

It is an amenable number.

391657797 is a deficient number, since it is larger than the sum of its proper divisors (182039067).

391657797 is a wasteful number, since it uses less digits than its factorization.

391657797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 613000 (or 612997 counting only the distinct ones).

The product of its digits is 2500470, while the sum is 54.

The square root of 391657797 is about 19790.3460555898. The cubic root of 391657797 is about 731.6481165025.

The spelling of 391657797 in words is "three hundred ninety-one million, six hundred fifty-seven thousand, seven hundred ninety-seven".