667656765 has 48 divisors (see below), whose sum is σ = 1246602240. Its totient is φ = 329598720.

The previous prime is 667656727. The next prime is 667656791. The reversal of 667656765 is 567656766.

667656765 is a `hidden beast` number, since 6 + 6 + 76 + 567 + 6 + 5 = 666.

It is not a de Polignac number, because 667656765 - 2¹⁴ = 667640381 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 21681 + ... + 42489.

It is an arithmetic number, because the mean of its divisors is an integer number (25970880).

Almost surely, 2^667656765 is an apocalyptic number.

It is an amenable number.

667656765 is a deficient number, since it is larger than the sum of its proper divisors (578945475).

667656765 is a wasteful number, since it uses less digits than its factorization.

667656765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20874 (or 20871 counting only the distinct ones).

The product of its digits is 9525600, while the sum is 54.

The square root of 667656765 is about 25839.0550330309. The cubic root of 667656765 is about 874.0127161023.

Subtracting from 667656765 its reverse (567656766), we obtain a palindrome (99999999).

The spelling of 667656765 in words is "six hundred sixty-seven million, six hundred fifty-six thousand, seven hundred sixty-five".