201645121 has 4 divisors (see below), whose sum is σ = 201817044. Its totient is φ = 201473200.

The previous prime is 201645113. The next prime is 201645137. The reversal of 201645121 is 121546102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 98724096 + 102921025 = 9936^2 + 10145^2 .

It is a cyclic number.

It is not a de Polignac number, because 201645121 - 2³ = 201645113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 201645092 and 201645101.

It is not an unprimeable number, because it can be changed into a prime (201645151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84190 + ... + 86551.

It is an arithmetic number, because the mean of its divisors is an integer number (50454261).

Almost surely, 2^201645121 is an apocalyptic number.

It is an amenable number.

201645121 is a deficient number, since it is larger than the sum of its proper divisors (171923).

201645121 is a wasteful number, since it uses less digits than its factorization.

201645121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171922.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 201645121 is about 14200.1803157566. The cubic root of 201645121 is about 586.4026254918.

The spelling of 201645121 in words is "two hundred one million, six hundred forty-five thousand, one hundred twenty-one".