1661666353 has 2 divisors, whose sum is σ = 1661666354. Its totient is φ = 1661666352.

The previous prime is 1661666339. The next prime is 1661666387. The reversal of 1661666353 is 3536661661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1556460304 + 105206049 = 39452^2 + 10257^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661666353 - 2²⁵ = 1628111921 is a prime.

It is a super-2 number, since 2×1661666353² = 5522270137384641218, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1661666333) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830833176 + 830833177.

It is an arithmetic number, because the mean of its divisors is an integer number (830833177).

Almost surely, 2^1661666353 is an apocalyptic number.

It is an amenable number.

1661666353 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661666353 is an equidigital number, since it uses as much as digits as its factorization.

1661666353 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 349920, while the sum is 43.

The square root of 1661666353 is about 40763.5419584707. The cubic root of 1661666353 is about 1184.4442082564. Note that the first 3 decimals are identical.

The spelling of 1661666353 in words is "one billion, six hundred sixty-one million, six hundred sixty-six thousand, three hundred fifty-three".