1666663553 has 8 divisors (see below), whose sum is σ = 1745961600. Its totient is φ = 1588820688.

The previous prime is 1666663549. The next prime is 1666663567. The reversal of 1666663553 is 3553666661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1666663553 - 2² = 1666663549 is a prime.

It is a super-3 number, since 3×1666663553³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1666663498 and 1666663507.

It is not an unprimeable number, because it can be changed into a prime (1666663543) 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 7 ways as a sum of consecutive naturals, for example, 361451 + ... + 366032.

It is an arithmetic number, because the mean of its divisors is an integer number (218245200).

Almost surely, 2^1666663553 is an apocalyptic number.

It is an amenable number.

1666663553 is a deficient number, since it is larger than the sum of its proper divisors (79298047).

1666663553 is an equidigital number, since it uses as much as digits as its factorization.

1666663553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 727591.

The product of its digits is 1749600, while the sum is 47.

The square root of 1666663553 is about 40824.7909118957. The cubic root of 1666663553 is about 1185.6303631642.

The spelling of 1666663553 in words is "one billion, six hundred sixty-six million, six hundred sixty-three thousand, five hundred fifty-three".