1660601665 has 4 divisors (see below), whose sum is σ = 1992722004. Its totient is φ = 1328481328.

The previous prime is 1660601659. The next prime is 1660601687. The reversal of 1660601665 is 5661060661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5661060661 = 10253 ⋅552137.

It can be written as a sum of positive squares in 2 ways, for example, as 1111355569 + 549246096 = 33337^2 + 23436^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1660601665 is a prime.

It is a Duffinian 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, 166060162 + ... + 166060171.

It is an arithmetic number, because the mean of its divisors is an integer number (498180501).

Almost surely, 2^1660601665 is an apocalyptic number.

It is an amenable number.

1660601665 is a deficient number, since it is larger than the sum of its proper divisors (332120339).

1660601665 is an equidigital number, since it uses as much as digits as its factorization.

1660601665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332120338.

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 1660601665 is about 40750.4805493138. The cubic root of 1660601665 is about 1184.1911825382.

The spelling of 1660601665 in words is "one billion, six hundred sixty million, six hundred one thousand, six hundred sixty-five".