1666506823 has 2 divisors, whose sum is σ = 1666506824. Its totient is φ = 1666506822.

The previous prime is 1666506811. The next prime is 1666506833. The reversal of 1666506823 is 3286056661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1666506823 - 2²⁹ = 1129635911 is a prime.

It is a super-2 number, since 2×1666506823² = 5554489982211106658, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1666506823.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666506833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833253411 + 833253412.

It is an arithmetic number, because the mean of its divisors is an integer number (833253412).

Almost surely, 2^1666506823 is an apocalyptic number.

1666506823 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666506823 is an equidigital number, since it uses as much as digits as its factorization.

1666506823 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 311040, while the sum is 43.

The square root of 1666506823 is about 40822.8713223360. The cubic root of 1666506823 is about 1185.5931971604.

The spelling of 1666506823 in words is "one billion, six hundred sixty-six million, five hundred six thousand, eight hundred twenty-three".