201705660661 has 4 divisors (see below), whose sum is σ = 208661028300. Its totient is φ = 194750293024.

The previous prime is 201705660643. The next prime is 201705660677. The reversal of 201705660661 is 166066507102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166066507102 = 2 ⋅83033253551.

It can be written as a sum of positive squares in 2 ways, for example, as 137367338161 + 64338322500 = 370631^2 + 253650^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201705660661 is a prime.

It is a super-3 number, since 3×201705660661³ (a number of 35 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201705960661) 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, 3477683776 + ... + 3477683833.

It is an arithmetic number, because the mean of its divisors is an integer number (52165257075).

Almost surely, 2^201705660661 is an apocalyptic number.

It is an amenable number.

201705660661 is a deficient number, since it is larger than the sum of its proper divisors (6955367639).

201705660661 is an equidigital number, since it uses as much as digits as its factorization.

201705660661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6955367638.

The product of its (nonzero) digits is 90720, while the sum is 40.

The spelling of 201705660661 in words is "two hundred one billion, seven hundred five million, six hundred sixty thousand, six hundred sixty-one".