685187217251 has 2 divisors, whose sum is σ = 685187217252. Its totient is φ = 685187217250.

The previous prime is 685187217203. The next prime is 685187217283. The reversal of 685187217251 is 152712781586.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 685187217251 - 2³⁴ = 668007348067 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 685187217193 and 685187217202.

It is not a weakly prime, because it can be changed into another prime (685187217551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342593608625 + 342593608626.

It is an arithmetic number, because the mean of its divisors is an integer number (342593608626).

Almost surely, 2^685187217251 is an apocalyptic number.

685187217251 is a deficient number, since it is larger than the sum of its proper divisors (1).

685187217251 is an equidigital number, since it uses as much as digits as its factorization.

685187217251 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1881600, while the sum is 53.

The spelling of 685187217251 in words is "six hundred eighty-five billion, one hundred eighty-seven million, two hundred seventeen thousand, two hundred fifty-one".