678813391961 has 2 divisors, whose sum is σ = 678813391962. Its totient is φ = 678813391960.

The previous prime is 678813391933. The next prime is 678813391999. The reversal of 678813391961 is 169193318876.

678813391961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 501441015625 + 177372376336 = 708125^2 + 421156^2 .

It is a cyclic number.

It is not a de Polignac number, because 678813391961 - 2²² = 678809197657 is a prime.

It is a super-2 number, since 2×678813391961² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 678813391894 and 678813391903.

It is not a weakly prime, because it can be changed into another prime (678813391561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339406695980 + 339406695981.

It is an arithmetic number, because the mean of its divisors is an integer number (339406695981).

Almost surely, 2^678813391961 is an apocalyptic number.

It is an amenable number.

678813391961 is a deficient number, since it is larger than the sum of its proper divisors (1).

678813391961 is an equidigital number, since it uses as much as digits as its factorization.

678813391961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11757312, while the sum is 62.

The spelling of 678813391961 in words is "six hundred seventy-eight billion, eight hundred thirteen million, three hundred ninety-one thousand, nine hundred sixty-one".