678000520861 has 2 divisors, whose sum is σ = 678000520862. Its totient is φ = 678000520860.

The previous prime is 678000520831. The next prime is 678000520913. The reversal of 678000520861 is 168025000876.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 677997440836 + 3080025 = 823406^2 + 1755^2 .

It is a cyclic number.

It is not a de Polignac number, because 678000520861 - 2¹¹ = 678000518813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (678000520831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339000260430 + 339000260431.

It is an arithmetic number, because the mean of its divisors is an integer number (339000260431).

Almost surely, 2^678000520861 is an apocalyptic number.

It is an amenable number.

678000520861 is a deficient number, since it is larger than the sum of its proper divisors (1).

678000520861 is an equidigital number, since it uses as much as digits as its factorization.

678000520861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 161280, while the sum is 43.

The spelling of 678000520861 in words is "six hundred seventy-eight billion, five hundred twenty thousand, eight hundred sixty-one".