667894456779 has 24 divisors (see below), whose sum is σ = 999669027840. Its totient is φ = 396172072560.

The previous prime is 667894456739. The next prime is 667894456781. The reversal of 667894456779 is 977654498766.

It is not a de Polignac number, because 667894456779 - 2⁷ = 667894456651 is a prime.

It is a super-2 number, since 2×667894456779² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (667894456739) 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 23 ways as a sum of consecutive naturals, for example, 19556659 + ... + 19590780.

It is an arithmetic number, because the mean of its divisors is an integer number (41652876160).

Almost surely, 2^667894456779 is an apocalyptic number.

667894456779 is a deficient number, since it is larger than the sum of its proper divisors (331774571061).

667894456779 is a wasteful number, since it uses less digits than its factorization.

667894456779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39147511 (or 39147500 counting only the distinct ones).

The product of its digits is 3840721920, while the sum is 78.

The spelling of 667894456779 in words is "six hundred sixty-seven billion, eight hundred ninety-four million, four hundred fifty-six thousand, seven hundred seventy-nine".