678872391 has 4 divisors (see below), whose sum is σ = 905163192. Its totient is φ = 452581592.

The previous prime is 678872387. The next prime is 678872399. The reversal of 678872391 is 193278876.

678872391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 678872391 - 2² = 678872387 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (678872399) 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, 113145396 + ... + 113145401.

It is an arithmetic number, because the mean of its divisors is an integer number (226290798).

Almost surely, 2^678872391 is an apocalyptic number.

678872391 is a deficient number, since it is larger than the sum of its proper divisors (226290801).

678872391 is a wasteful number, since it uses less digits than its factorization.

678872391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226290800.

The product of its digits is 1016064, while the sum is 51.

The square root of 678872391 is about 26055.1797345557. The cubic root of 678872391 is about 878.8795964202.

The spelling of 678872391 in words is "six hundred seventy-eight million, eight hundred seventy-two thousand, three hundred ninety-one".