391078139 has 4 divisors (see below), whose sum is σ = 391263960. Its totient is φ = 390892320.

The previous prime is 391078133. The next prime is 391078169. The reversal of 391078139 is 931870193.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 931870193 = 12451 ⋅74843.

It is a cyclic number.

It is not a de Polignac number, because 391078139 - 2¹² = 391074043 is a prime.

It is a super-2 number, since 2×391078139² = 305884221607406642, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 391078096 and 391078105.

It is not an unprimeable number, because it can be changed into a prime (391078133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89717 + ... + 93974.

It is an arithmetic number, because the mean of its divisors is an integer number (97815990).

Almost surely, 2^391078139 is an apocalyptic number.

391078139 is a deficient number, since it is larger than the sum of its proper divisors (185821).

391078139 is a wasteful number, since it uses less digits than its factorization.

391078139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185820.

The product of its (nonzero) digits is 40824, while the sum is 41.

The square root of 391078139 is about 19775.6956641227. The cubic root of 391078139 is about 731.2869891047.

The spelling of 391078139 in words is "three hundred ninety-one million, seventy-eight thousand, one hundred thirty-nine".