2121311666 has 16 divisors (see below), whose sum is σ = 3340695744. Its totient is φ = 1008312624.

The previous prime is 2121311653. The next prime is 2121311671. The reversal of 2121311666 is 6661131212.

It is a happy number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 133961 + ... + 148956.

It is an arithmetic number, because the mean of its divisors is an integer number (208793484).

Almost surely, 2^2121311666 is an apocalyptic number.

2121311666 is a deficient number, since it is larger than the sum of its proper divisors (1219384078).

2121311666 is a wasteful number, since it uses less digits than its factorization.

2121311666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283105.

The product of its digits is 2592, while the sum is 29.

The square root of 2121311666 is about 46057.6993129270. The cubic root of 2121311666 is about 1284.8965414038.

Adding to 2121311666 its reverse (6661131212), we get a palindrome (8782442878).

The spelling of 2121311666 in words is "two billion, one hundred twenty-one million, three hundred eleven thousand, six hundred sixty-six".