391988115 has 12 divisors (see below), whose sum is σ = 679446144. Its totient is φ = 209060304.

The previous prime is 391988081. The next prime is 391988119. The reversal of 391988115 is 511889193.

It is not a de Polignac number, because 391988115 - 2¹⁷ = 391857043 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 8710847 = 391988115 / (3 + 9 + 1 + 9 + 8 + 8 + 1 + 1 + 5).

It is not an unprimeable number, because it can be changed into a prime (391988119) 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, 4355379 + ... + 4355468.

It is an arithmetic number, because the mean of its divisors is an integer number (56620512).

Almost surely, 2^391988115 is an apocalyptic number.

391988115 is a deficient number, since it is larger than the sum of its proper divisors (287458029).

391988115 is a wasteful number, since it uses less digits than its factorization.

391988115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8710858 (or 8710855 counting only the distinct ones).

The product of its digits is 77760, while the sum is 45.

The square root of 391988115 is about 19798.6897293735. The cubic root of 391988115 is about 731.8537455271.

The spelling of 391988115 in words is "three hundred ninety-one million, nine hundred eighty-eight thousand, one hundred fifteen".