201866981 has 2 divisors, whose sum is σ = 201866982. Its totient is φ = 201866980.

The previous prime is 201866969. The next prime is 201867007. The reversal of 201866981 is 189668102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 114276100 + 87590881 = 10690^2 + 9359^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201866981 is a prime.

It is a super-2 number, since 2×201866981² = 81500556036108722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201866911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100933490 + 100933491.

It is an arithmetic number, because the mean of its divisors is an integer number (100933491).

Almost surely, 2^201866981 is an apocalyptic number.

It is an amenable number.

201866981 is a deficient number, since it is larger than the sum of its proper divisors (1).

201866981 is an equidigital number, since it uses as much as digits as its factorization.

201866981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 201866981 is about 14207.9900408186. The cubic root of 201866981 is about 586.6176097854.

The spelling of 201866981 in words is "two hundred one million, eight hundred sixty-six thousand, nine hundred eighty-one".