684806565881 has 2 divisors, whose sum is σ = 684806565882. Its totient is φ = 684806565880.

The previous prime is 684806565809. The next prime is 684806565887. The reversal of 684806565881 is 188565608486.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 684127494400 + 679071481 = 827120^2 + 26059^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-684806565881 is a prime.

It is a super-2 number, since 2×684806565881² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (684806565887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342403282940 + 342403282941.

It is an arithmetic number, because the mean of its divisors is an integer number (342403282941).

Almost surely, 2^684806565881 is an apocalyptic number.

It is an amenable number.

684806565881 is a deficient number, since it is larger than the sum of its proper divisors (1).

684806565881 is an equidigital number, since it uses as much as digits as its factorization.

684806565881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 88473600, while the sum is 65.

The spelling of 684806565881 in words is "six hundred eighty-four billion, eight hundred six million, five hundred sixty-five thousand, eight hundred eighty-one".