686178379 has 4 divisors (see below), whose sum is σ = 686251440. Its totient is φ = 686105320.

The previous prime is 686178371. The next prime is 686178403. The reversal of 686178379 is 973871686.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 973871686 = 2 ⋅486935843.

It is a cyclic number.

It is not a de Polignac number, because 686178379 - 2³ = 686178371 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686178371) 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, 19927 + ... + 42064.

It is an arithmetic number, because the mean of its divisors is an integer number (171562860).

Almost surely, 2^686178379 is an apocalyptic number.

686178379 is a deficient number, since it is larger than the sum of its proper divisors (73061).

686178379 is a wasteful number, since it uses less digits than its factorization.

686178379 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73060.

The product of its digits is 3048192, while the sum is 55.

The square root of 686178379 is about 26195.0067570138. The cubic root of 686178379 is about 882.0211716543.

The spelling of 686178379 in words is "six hundred eighty-six million, one hundred seventy-eight thousand, three hundred seventy-nine".