1666497265 has 4 divisors (see below), whose sum is σ = 1999796724. Its totient is φ = 1333197808.

The previous prime is 1666497263. The next prime is 1666497299. The reversal of 1666497265 is 5627946661.

It is a happy number.

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 456292321 + 1210204944 = 21361^2 + 34788^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666497265 - 2¹ = 1666497263 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666497263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166649722 + ... + 166649731.

It is an arithmetic number, because the mean of its divisors is an integer number (499949181).

Almost surely, 2^1666497265 is an apocalyptic number.

It is an amenable number.

1666497265 is a deficient number, since it is larger than the sum of its proper divisors (333299459).

1666497265 is an equidigital number, since it uses as much as digits as its factorization.

1666497265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333299458.

The product of its digits is 3265920, while the sum is 52.

The square root of 1666497265 is about 40822.7542554395. The cubic root of 1666497265 is about 1185.5909305587.

The spelling of 1666497265 in words is "one billion, six hundred sixty-six million, four hundred ninety-seven thousand, two hundred sixty-five".