667231407778 has 16 divisors (see below), whose sum is σ = 1077853001400. Its totient is φ = 307947914496.

The previous prime is 667231407751. The next prime is 667231407781. The reversal of 667231407778 is 877704132766.

It is a happy number.

667231407778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 622989754209 + 44241653569 = 789297^2 + 210337^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1754826 + ... + 2100922.

Almost surely, 2^667231407778 is an apocalyptic number.

667231407778 is a deficient number, since it is larger than the sum of its proper divisors (410621593622).

667231407778 is a wasteful number, since it uses less digits than its factorization.

667231407778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 420261.

The product of its (nonzero) digits is 16595712, while the sum is 58.

The spelling of 667231407778 in words is "six hundred sixty-seven billion, two hundred thirty-one million, four hundred seven thousand, seven hundred seventy-eight".