123345666778 has 4 divisors (see below), whose sum is σ = 185018500170. Its totient is φ = 61672833388.

The previous prime is 123345666757. The next prime is 123345666811. The reversal of 123345666778 is 877666543321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 122614126569 + 731540209 = 350163^2 + 27047^2 .

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a plaindrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30836416693 + ... + 30836416696.

Almost surely, 2^123345666778 is an apocalyptic number.

123345666778 is a deficient number, since it is larger than the sum of its proper divisors (61672833392).

123345666778 is an equidigital number, since it uses as much as digits as its factorization.

123345666778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61672833391.

The product of its digits is 30481920, while the sum is 58.

The spelling of 123345666778 in words is "one hundred twenty-three billion, three hundred forty-five million, six hundred sixty-six thousand, seven hundred seventy-eight".