667643823 has 64 divisors (see below), whose sum is σ = 1254297600. Its totient is φ = 340886880.

The previous prime is 667643803. The next prime is 667643863. The reversal of 667643823 is 328346766.

It is not a de Polignac number, because 667643823 - 2⁵ = 667643791 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667643803) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 119940 + ... + 125382.

It is an arithmetic number, because the mean of its divisors is an integer number (19598400).

Almost surely, 2^667643823 is an apocalyptic number.

667643823 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

667643823 is a deficient number, since it is larger than the sum of its proper divisors (586653777).

667643823 is a wasteful number, since it uses less digits than its factorization.

667643823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5529 (or 5523 counting only the distinct ones).

The product of its digits is 870912, while the sum is 45.

The square root of 667643823 is about 25838.8045969623. The cubic root of 667643823 is about 874.0070687166.

The spelling of 667643823 in words is "six hundred sixty-seven million, six hundred forty-three thousand, eight hundred twenty-three".