2666996661 has 8 divisors (see below), whose sum is σ = 4063994944. Its totient is φ = 1523998080.

The previous prime is 2666996653. The next prime is 2666996711. The reversal of 2666996661 is 1666996662.

It is a happy number.

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

It is not a de Polignac number, because 2666996661 - 2³ = 2666996653 is a prime.

It is a super-2 number, since 2×2666996661² = 14225742379570297842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2666996641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63499900 + ... + 63499941.

It is an arithmetic number, because the mean of its divisors is an integer number (507999368).

Almost surely, 2^2666996661 is an apocalyptic number.

2666996661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2666996661 is a deficient number, since it is larger than the sum of its proper divisors (1396998283).

2666996661 is a wasteful number, since it uses less digits than its factorization.

2666996661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126999851.

The product of its digits is 7558272, while the sum is 57.

The square root of 2666996661 is about 51642.9730069832. The cubic root of 2666996661 is about 1386.7797476648.

Subtracting from 2666996661 its reverse (1666996662), we obtain a palindrome (999999999).

The spelling of 2666996661 in words is "two billion, six hundred sixty-six million, nine hundred ninety-six thousand, six hundred sixty-one".