866786515816061 has 2 divisors, whose sum is σ = 866786515816062. Its totient is φ = 866786515816060.

The previous prime is 866786515816057. The next prime is 866786515816121. The reversal of 866786515816061 is 160618515687668.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 708258422265625 + 158528093550436 = 26613125^2 + 12590794^2 .

It is a cyclic number.

It is not a de Polignac number, because 866786515816061 - 2² = 866786515816057 is a prime.

It is a super-2 number, since 2×866786515816061² (a number of 31 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 866786515816061.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866786515816021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433393257908030 + 433393257908031.

It is an arithmetic number, because the mean of its divisors is an integer number (433393257908031).

Almost surely, 2^{866786515816061} is an apocalyptic number.

It is an amenable number.

866786515816061 is a deficient number, since it is larger than the sum of its proper divisors (1).

866786515816061 is an equidigital number, since it uses as much as digits as its factorization.

866786515816061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 696729600, while the sum is 74.

The spelling of 866786515816061 in words is "eight hundred sixty-six trillion, seven hundred eighty-six billion, five hundred fifteen million, eight hundred sixteen thousand, sixty-one".