1666255513 has 12 divisors (see below), whose sum is σ = 1807887340. Its totient is φ = 1526631552.

The previous prime is 1666255501. The next prime is 1666255517. The reversal of 1666255513 is 3155526661.

It can be written as a sum of positive squares in 6 ways, for example, as 12369289 + 1653886224 = 3517^2 + 40668^2 .

It is not a de Polignac number, because 1666255513 - 2¹⁷ = 1666124441 is a prime.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666255517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 240583 + ... + 247411.

Almost surely, 2^1666255513 is an apocalyptic number.

1666255513 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1666255513 is a deficient number, since it is larger than the sum of its proper divisors (141631827).

1666255513 is an equidigital number, since it uses as much as digits as its factorization.

1666255513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7116 (or 6979 counting only the distinct ones).

The product of its digits is 162000, while the sum is 40.

The square root of 1666255513 is about 40819.7931523422. The cubic root of 1666255513 is about 1185.5335981635.

The spelling of 1666255513 in words is "one billion, six hundred sixty-six million, two hundred fifty-five thousand, five hundred thirteen".