201685221 has 20 divisors (see below), whose sum is σ = 302389164. Its totient is φ = 133963200.

The previous prime is 201685177. The next prime is 201685259. The reversal of 201685221 is 122586102.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 177182721 + 24502500 = 13311^2 + 4950^2 .

It is not a de Polignac number, because 201685221 - 2¹³ = 201677029 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201685291) 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 in 19 ways as a sum of consecutive naturals, for example, 18331 + ... + 27191.

Almost surely, 2^201685221 is an apocalyptic number.

It is an amenable number.

201685221 is a deficient number, since it is larger than the sum of its proper divisors (100703943).

201685221 is an equidigital number, since it uses as much as digits as its factorization.

201685221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9154 (or 9145 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 201685221 is about 14201.5921994683. The cubic root of 201685221 is about 586.4414944159.

The spelling of 201685221 in words is "two hundred one million, six hundred eighty-five thousand, two hundred twenty-one".