166746127778 has 4 divisors (see below), whose sum is σ = 250119191670. Its totient is φ = 83373063888.

The previous prime is 166746127759. The next prime is 166746127787. The reversal of 166746127778 is 877721647661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 877721647661 = 745103 ⋅1177987.

It can be written as a sum of positive squares in only one way, i.e., 148766804209 + 17979323569 = 385703^2 + 134087^2 .

It is a super-2 number, since 2×166746127778² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 166746127778.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 41686531943 + ... + 41686531946.

Almost surely, 2^166746127778 is an apocalyptic number.

166746127778 is a deficient number, since it is larger than the sum of its proper divisors (83373063892).

166746127778 is an equidigital number, since it uses as much as digits as its factorization.

166746127778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83373063891.

The product of its digits is 33191424, while the sum is 62.

The spelling of 166746127778 in words is "one hundred sixty-six billion, seven hundred forty-six million, one hundred twenty-seven thousand, seven hundred seventy-eight".