206066515981 has 2 divisors, whose sum is σ = 206066515982. Its totient is φ = 206066515980.

The previous prime is 206066515933. The next prime is 206066516011. The reversal of 206066515981 is 189515660602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151947938025 + 54118577956 = 389805^2 + 232634^2 .

It is a cyclic number.

It is not a de Polignac number, because 206066515981 - 2⁹ = 206066515469 is a prime.

It is a super-2 number, since 2×206066515981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206066515901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103033257990 + 103033257991.

It is an arithmetic number, because the mean of its divisors is an integer number (103033257991).

Almost surely, 2^206066515981 is an apocalyptic number.

It is an amenable number.

206066515981 is a deficient number, since it is larger than the sum of its proper divisors (1).

206066515981 is an equidigital number, since it uses as much as digits as its factorization.

206066515981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 777600, while the sum is 49.

The spelling of 206066515981 in words is "two hundred six billion, sixty-six million, five hundred fifteen thousand, nine hundred eighty-one".