201661589 has 2 divisors, whose sum is σ = 201661590. Its totient is φ = 201661588.

The previous prime is 201661571. The next prime is 201661597. The reversal of 201661589 is 985166102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 201157489 + 504100 = 14183^2 + 710^2 .

It is a cyclic number.

It is not a de Polignac number, because 201661589 - 2⁸ = 201661333 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201661289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100830794 + 100830795.

It is an arithmetic number, because the mean of its divisors is an integer number (100830795).

Almost surely, 2^201661589 is an apocalyptic number.

It is an amenable number.

201661589 is a deficient number, since it is larger than the sum of its proper divisors (1).

201661589 is an equidigital number, since it uses as much as digits as its factorization.

201661589 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 201661589 is about 14200.7601557100. The cubic root of 201661589 is about 586.4185885453.

The spelling of 201661589 in words is "two hundred one million, six hundred sixty-one thousand, five hundred eighty-nine".