205168676681 has 6 divisors (see below), whose sum is σ = 214476896970. Its totient is φ = 196248298928.

The previous prime is 205168676677. The next prime is 205168676683. The reversal of 205168676681 is 186676861502.

It can be written as a sum of positive squares in only one way, i.e., 174072528400 + 31096148281 = 417220^2 + 176341^2 .

It is not a de Polignac number, because 205168676681 - 2² = 205168676677 is a prime.

It is a super-2 number, since 2×205168676681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205168676683) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 193920716 + ... + 193921773.

It is an arithmetic number, because the mean of its divisors is an integer number (35746149495).

Almost surely, 2^205168676681 is an apocalyptic number.

It is an amenable number.

205168676681 is a deficient number, since it is larger than the sum of its proper divisors (9308220289).

205168676681 is an equidigital number, since it uses as much as digits as its factorization.

205168676681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 387842535 (or 387842512 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 56.

The spelling of 205168676681 in words is "two hundred five billion, one hundred sixty-eight million, six hundred seventy-six thousand, six hundred eighty-one".