1666220722007 has 2 divisors, whose sum is σ = 1666220722008. Its totient is φ = 1666220722006.

The previous prime is 1666220721961. The next prime is 1666220722009. The reversal of 1666220722007 is 7002270226661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1666220722007 - 2⁸ = 1666220721751 is a prime.

Together with 1666220722009, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666220722009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833110361003 + 833110361004.

It is an arithmetic number, because the mean of its divisors is an integer number (833110361004).

Almost surely, 2^{1666220722007} is an apocalyptic number.

1666220722007 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666220722007 is an equidigital number, since it uses as much as digits as its factorization.

1666220722007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 169344, while the sum is 41.

Adding to 1666220722007 its reverse (7002270226661), we get a palindrome (8668490948668).

The spelling of 1666220722007 in words is "one trillion, six hundred sixty-six billion, two hundred twenty million, seven hundred twenty-two thousand, seven".