166506506651 has 2 divisors, whose sum is σ = 166506506652. Its totient is φ = 166506506650.

The previous prime is 166506506599. The next prime is 166506506671. The reversal of 166506506651 is 156605605661.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166506506651 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 166506506596 and 166506506605.

It is not a weakly prime, because it can be changed into another prime (166506506671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83253253325 + 83253253326.

It is an arithmetic number, because the mean of its divisors is an integer number (83253253326).

Almost surely, 2^166506506651 is an apocalyptic number.

166506506651 is a deficient number, since it is larger than the sum of its proper divisors (1).

166506506651 is an equidigital number, since it uses as much as digits as its factorization.

166506506651 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972000, while the sum is 47.

The spelling of 166506506651 in words is "one hundred sixty-six billion, five hundred six million, five hundred six thousand, six hundred fifty-one".