201685681 has 2 divisors, whose sum is σ = 201685682. Its totient is φ = 201685680.

The previous prime is 201685667. The next prime is 201685699. The reversal of 201685681 is 186586102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 191573281 + 10112400 = 13841^2 + 3180^2 .

It is a cyclic number.

It is not a de Polignac number, because 201685681 - 2⁷ = 201685553 is a prime.

It is a super-2 number, since 2×201685681² = 81354227840867522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 201685681.

It is not a weakly prime, because it can be changed into another prime (201685661) 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, 100842840 + 100842841.

It is an arithmetic number, because the mean of its divisors is an integer number (100842841).

Almost surely, 2^201685681 is an apocalyptic number.

It is an amenable number.

201685681 is a deficient number, since it is larger than the sum of its proper divisors (1).

201685681 is an equidigital number, since it uses as much as digits as its factorization.

201685681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23040, while the sum is 37.

The square root of 201685681 is about 14201.6083948263. The cubic root of 201685681 is about 586.4419402639.

The spelling of 201685681 in words is "two hundred one million, six hundred eighty-five thousand, six hundred eighty-one".