166056778751 has 4 divisors (see below), whose sum is σ = 171782874600. Its totient is φ = 160330682904.

The previous prime is 166056778709. The next prime is 166056778763. The reversal of 166056778751 is 157877650661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 157877650661 = 126653 ⋅1246537.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166056778751 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166056778051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2863047881 + ... + 2863047938.

It is an arithmetic number, because the mean of its divisors is an integer number (42945718650).

Almost surely, 2^166056778751 is an apocalyptic number.

166056778751 is a deficient number, since it is larger than the sum of its proper divisors (5726095849).

166056778751 is an equidigital number, since it uses as much as digits as its factorization.

166056778751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5726095848.

The product of its (nonzero) digits is 14817600, while the sum is 59.

The spelling of 166056778751 in words is "one hundred sixty-six billion, fifty-six million, seven hundred seventy-eight thousand, seven hundred fifty-one".