678693731 has 2 divisors, whose sum is σ = 678693732. Its totient is φ = 678693730.

The previous prime is 678693721. The next prime is 678693761. The reversal of 678693731 is 137396876.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 678693731 - 2⁶ = 678693667 is a prime.

It is a super-2 number, since 2×678693731² = 921250360997400722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 678693731.

It is not a weakly prime, because it can be changed into another prime (678693721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339346865 + 339346866.

It is an arithmetic number, because the mean of its divisors is an integer number (339346866).

Almost surely, 2^678693731 is an apocalyptic number.

678693731 is a deficient number, since it is larger than the sum of its proper divisors (1).

678693731 is an equidigital number, since it uses as much as digits as its factorization.

678693731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1143072, while the sum is 50.

The square root of 678693731 is about 26051.7510160066. The cubic root of 678693731 is about 878.8024909105.

The spelling of 678693731 in words is "six hundred seventy-eight million, six hundred ninety-three thousand, seven hundred thirty-one".