391959399 has 16 divisors (see below), whose sum is σ = 587284992. Its totient is φ = 230718048.

The previous prime is 391959397. The next prime is 391959401. The reversal of 391959399 is 993959193.

It is an interprime number because it is at equal distance from previous prime (391959397) and next prime (391959401).

It is not a de Polignac number, because 391959399 - 2¹ = 391959397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391959391) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 217587 + ... + 219380.

It is an arithmetic number, because the mean of its divisors is an integer number (36705312).

Almost surely, 2^391959399 is an apocalyptic number.

391959399 is a gapful number since it is divisible by the number (39) formed by its first and last digit.

391959399 is a deficient number, since it is larger than the sum of its proper divisors (195325593).

391959399 is a wasteful number, since it uses less digits than its factorization.

391959399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437006.

The product of its digits is 2657205, while the sum is 57.

The square root of 391959399 is about 19797.9645165860. The cubic root of 391959399 is about 731.8358738752.

The spelling of 391959399 in words is "three hundred ninety-one million, nine hundred fifty-nine thousand, three hundred ninety-nine".