1666839563923 has 2 divisors, whose sum is σ = 1666839563924. Its totient is φ = 1666839563922.

The previous prime is 1666839563899. The next prime is 1666839563941. The reversal of 1666839563923 is 3293659386661.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666839563923 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666839563723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833419781961 + 833419781962.

It is an arithmetic number, because the mean of its divisors is an integer number (833419781962).

Almost surely, 2^{1666839563923} is an apocalyptic number.

1666839563923 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666839563923 is an equidigital number, since it uses as much as digits as its factorization.

1666839563923 is an evil number, because the sum of its binary digits is even.

The product of its digits is 226748160, while the sum is 67.

The spelling of 1666839563923 in words is "one trillion, six hundred sixty-six billion, eight hundred thirty-nine million, five hundred sixty-three thousand, nine hundred twenty-three".