667780778 has 16 divisors (see below), whose sum is σ = 1145135040. Its totient is φ = 286099776.

The previous prime is 667780777. The next prime is 667780793. The reversal of 667780778 is 877087766.

It is not an unprimeable number, because it can be changed into a prime (667780777) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55250 + ... + 66242.

It is an arithmetic number, because the mean of its divisors is an integer number (71570940).

Almost surely, 2^667780778 is an apocalyptic number.

667780778 is a deficient number, since it is larger than the sum of its proper divisors (477354262).

667780778 is a wasteful number, since it uses less digits than its factorization.

667780778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15341.

The product of its (nonzero) digits is 5531904, while the sum is 56.

The square root of 667780778 is about 25841.4546417186. The cubic root of 667780778 is about 874.0668268542.

The spelling of 667780778 in words is "six hundred sixty-seven million, seven hundred eighty thousand, seven hundred seventy-eight".