166788681778 has 8 divisors (see below), whose sum is σ = 250335857772. Its totient is φ = 83343395856.

The previous prime is 166788681739. The next prime is 166788681781. The reversal of 166788681778 is 877186887661.

It can be written as a sum of positive squares in 2 ways, for example, as 151443170649 + 15345511129 = 389157^2 + 123877^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 166788681778.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25468425 + ... + 25474972.

Almost surely, 2^166788681778 is an apocalyptic number.

166788681778 is a deficient number, since it is larger than the sum of its proper divisors (83547175994).

166788681778 is a wasteful number, since it uses less digits than its factorization.

166788681778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50945036.

The product of its digits is 303464448, while the sum is 73.

The spelling of 166788681778 in words is "one hundred sixty-six billion, seven hundred eighty-eight million, six hundred eighty-one thousand, seven hundred seventy-eight".