667780769 has 4 divisors (see below), whose sum is σ = 668141460. Its totient is φ = 667420080.

The previous prime is 667780741. The next prime is 667780777. The reversal of 667780769 is 967087766.

667780769 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 305830144 + 361950625 = 17488^2 + 19025^2 .

It is a cyclic number.

It is not a de Polignac number, because 667780769 - 2⁸ = 667780513 is a prime.

It is a super-2 number, since 2×667780769² = 891862310892462722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (667780369) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 177554 + ... + 181275.

It is an arithmetic number, because the mean of its divisors is an integer number (167035365).

Almost surely, 2^667780769 is an apocalyptic number.

It is an amenable number.

667780769 is a deficient number, since it is larger than the sum of its proper divisors (360691).

667780769 is a wasteful number, since it uses less digits than its factorization.

667780769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360690.

The product of its (nonzero) digits is 5334336, while the sum is 56.

The square root of 667780769 is about 25841.4544675798. The cubic root of 667780769 is about 874.0668229275.

The spelling of 667780769 in words is "six hundred sixty-seven million, seven hundred eighty thousand, seven hundred sixty-nine".