2118943661 has 4 divisors (see below), whose sum is σ = 2134188000. Its totient is φ = 2103699324.

The previous prime is 2118943613. The next prime is 2118943679. The reversal of 2118943661 is 1663498112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2118943661 - 2¹⁸ = 2118681517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2118943691) 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, 7621961 + ... + 7622238.

It is an arithmetic number, because the mean of its divisors is an integer number (533547000).

Almost surely, 2^2118943661 is an apocalyptic number.

It is an amenable number.

2118943661 is a deficient number, since it is larger than the sum of its proper divisors (15244339).

2118943661 is a wasteful number, since it uses less digits than its factorization.

2118943661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15244338.

The product of its digits is 62208, while the sum is 41.

The square root of 2118943661 is about 46031.9851950793. The cubic root of 2118943661 is about 1284.4182564594.

The spelling of 2118943661 in words is "two billion, one hundred eighteen million, nine hundred forty-three thousand, six hundred sixty-one".