678640731827 has 2 divisors, whose sum is σ = 678640731828. Its totient is φ = 678640731826.

The previous prime is 678640731803. The next prime is 678640731877. The reversal of 678640731827 is 728137046876.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-678640731827 is a prime.

It is a super-2 number, since 2×678640731827² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (678640731877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339320365913 + 339320365914.

It is an arithmetic number, because the mean of its divisors is an integer number (339320365914).

Almost surely, 2^678640731827 is an apocalyptic number.

678640731827 is a deficient number, since it is larger than the sum of its proper divisors (1).

678640731827 is an equidigital number, since it uses as much as digits as its factorization.

678640731827 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18966528, while the sum is 59.

The spelling of 678640731827 in words is "six hundred seventy-eight billion, six hundred forty million, seven hundred thirty-one thousand, eight hundred twenty-seven".