391998859 has 8 divisors (see below), whose sum is σ = 448252160. Its totient is φ = 335808936.

The previous prime is 391998857. The next prime is 391998883. The reversal of 391998859 is 958899193.

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 391998859 - 2¹ = 391998857 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 391998797 and 391998806.

It is not an unprimeable number, because it can be changed into a prime (391998851) 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, 1749 + ... + 28054.

It is an arithmetic number, because the mean of its divisors is an integer number (56031520).

Almost surely, 2^391998859 is an apocalyptic number.

391998859 is a deficient number, since it is larger than the sum of its proper divisors (56253301).

391998859 is a wasteful number, since it uses less digits than its factorization.

391998859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31689.

The product of its digits is 6298560, while the sum is 61.

The square root of 391998859 is about 19798.9610586010. The cubic root of 391998859 is about 731.8604319243.

The spelling of 391998859 in words is "three hundred ninety-one million, nine hundred ninety-eight thousand, eight hundred fifty-nine".