667649943 has 12 divisors (see below), whose sum is σ = 971323080. Its totient is φ = 441896976.

The previous prime is 667649929. The next prime is 667649947. The reversal of 667649943 is 349946766.

It is not a de Polignac number, because 667649943 - 2²¹ = 665552791 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 667649943.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667649947) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 265596 + ... + 268097.

It is an arithmetic number, because the mean of its divisors is an integer number (80943590).

Almost surely, 2^667649943 is an apocalyptic number.

667649943 is a deficient number, since it is larger than the sum of its proper divisors (303673137).

667649943 is a wasteful number, since it uses less digits than its factorization.

667649943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533838 (or 533835 counting only the distinct ones).

The product of its digits is 5878656, while the sum is 54.

The square root of 667649943 is about 25838.9230232222. The cubic root of 667649943 is about 874.0097392558.

The spelling of 667649943 in words is "six hundred sixty-seven million, six hundred forty-nine thousand, nine hundred forty-three".