1966978169 has 4 divisors (see below), whose sum is σ = 2118284196. Its totient is φ = 1815672144.

The previous prime is 1966978163. The next prime is 1966978177. The reversal of 1966978169 is 9618796691.

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

It can be written as a sum of positive squares in 2 ways, for example, as 755590144 + 1211388025 = 27488^2 + 34805^2 .

It is not a de Polignac number, because 1966978169 - 2⁸ = 1966977913 is a prime.

It is a super-2 number, since 2×1966978169² = 7738006234645185122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1966978163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75652994 + ... + 75653019.

It is an arithmetic number, because the mean of its divisors is an integer number (529571049).

Almost surely, 2^1966978169 is an apocalyptic number.

It is an amenable number.

1966978169 is a deficient number, since it is larger than the sum of its proper divisors (151306027).

1966978169 is a wasteful number, since it uses less digits than its factorization.

1966978169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151306026.

The product of its digits is 8817984, while the sum is 62.

The square root of 1966978169 is about 44350.6276054804. The cubic root of 1966978169 is about 1252.9483828829.

The spelling of 1966978169 in words is "one billion, nine hundred sixty-six million, nine hundred seventy-eight thousand, one hundred sixty-nine".