201665770417 has 4 divisors (see below), whose sum is σ = 203744799076. Its totient is φ = 199586741760.

The previous prime is 201665770393. The next prime is 201665770483. The reversal of 201665770417 is 714077566102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 714077566102 = 2 ⋅357038783051.

It can be written as a sum of positive squares in 2 ways, for example, as 155870198416 + 45795572001 = 394804^2 + 213999^2 .

It is a cyclic number.

It is not a de Polignac number, because 201665770417 - 2⁷ = 201665770289 is a prime.

It is a super-3 number, since 3×201665770417³ (a number of 35 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (201665770487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1039514184 + ... + 1039514377.

It is an arithmetic number, because the mean of its divisors is an integer number (50936199769).

Almost surely, 2^201665770417 is an apocalyptic number.

It is an amenable number.

201665770417 is a deficient number, since it is larger than the sum of its proper divisors (2079028659).

201665770417 is an equidigital number, since it uses as much as digits as its factorization.

201665770417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2079028658.

The product of its (nonzero) digits is 493920, while the sum is 46.

The spelling of 201665770417 in words is "two hundred one billion, six hundred sixty-five million, seven hundred seventy thousand, four hundred seventeen".