667728667 has 2 divisors, whose sum is σ = 667728668. Its totient is φ = 667728666.

The previous prime is 667728653. The next prime is 667728727. The reversal of 667728667 is 766827766.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 667728667 - 2⁷ = 667728539 is a prime.

It is not a weakly prime, because it can be changed into another prime (667728637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333864333 + 333864334.

It is an arithmetic number, because the mean of its divisors is an integer number (333864334).

Almost surely, 2^667728667 is an apocalyptic number.

667728667 is a deficient number, since it is larger than the sum of its proper divisors (1).

667728667 is an equidigital number, since it uses as much as digits as its factorization.

667728667 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7112448, while the sum is 55.

The square root of 667728667 is about 25840.4463390244. The cubic root of 667728667 is about 874.0440900107.

Subtracting 667728667 from its reverse (766827766), we obtain a palindrome (99099099).

It can be divided in two parts, 6677 and 28667, that added together give a square (35344 = 188²).

The spelling of 667728667 in words is "six hundred sixty-seven million, seven hundred twenty-eight thousand, six hundred sixty-seven".