2131666321 has 2 divisors, whose sum is σ = 2131666322. Its totient is φ = 2131666320.

The previous prime is 2131666319. The next prime is 2131666333. The reversal of 2131666321 is 1236661312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2088947025 + 42719296 = 45705^2 + 6536^2 .

It is a cyclic number.

It is not a de Polignac number, because 2131666321 - 2¹ = 2131666319 is a prime.

Together with 2131666319, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2131666351) 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 as a sum of consecutive naturals, namely, 1065833160 + 1065833161.

It is an arithmetic number, because the mean of its divisors is an integer number (1065833161).

Almost surely, 2^2131666321 is an apocalyptic number.

It is an amenable number.

2131666321 is a deficient number, since it is larger than the sum of its proper divisors (1).

2131666321 is an equidigital number, since it uses as much as digits as its factorization.

2131666321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 31.

The square root of 2131666321 is about 46169.9720706002. The cubic root of 2131666321 is about 1286.9837831998.

The spelling of 2131666321 in words is "two billion, one hundred thirty-one million, six hundred sixty-six thousand, three hundred twenty-one".