201660565 has 4 divisors (see below), whose sum is σ = 241992684. Its totient is φ = 161328448.

The previous prime is 201660559. The next prime is 201660581. The reversal of 201660565 is 565066102.

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 62821476 + 138839089 = 7926^2 + 11783^2 .

It is a cyclic number.

It is not a de Polignac number, because 201660565 - 2⁵ = 201660533 is a prime.

It is a super-2 number, since 2×201660565² = 81333966952238450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20166052 + ... + 20166061.

It is an arithmetic number, because the mean of its divisors is an integer number (60498171).

Almost surely, 2^201660565 is an apocalyptic number.

It is an amenable number.

201660565 is a deficient number, since it is larger than the sum of its proper divisors (40332119).

201660565 is an equidigital number, since it uses as much as digits as its factorization.

201660565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40332118.

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 201660565 is about 14200.7241012562. The cubic root of 201660565 is about 586.4175959688.

The spelling of 201660565 in words is "two hundred one million, six hundred sixty thousand, five hundred sixty-five".