667638247 has 4 divisors (see below), whose sum is σ = 668086920. Its totient is φ = 667189576.

The previous prime is 667638233. The next prime is 667638281. The reversal of 667638247 is 742836766.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 667638247 - 2¹⁵ = 667605479 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 667638247.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667636247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 222097 + ... + 225082.

It is an arithmetic number, because the mean of its divisors is an integer number (167021730).

Almost surely, 2^667638247 is an apocalyptic number.

667638247 is a deficient number, since it is larger than the sum of its proper divisors (448673).

667638247 is a wasteful number, since it uses less digits than its factorization.

667638247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448672.

The product of its digits is 2032128, while the sum is 49.

The square root of 667638247 is about 25838.6966970085. The cubic root of 667638247 is about 874.0046355445.

The spelling of 667638247 in words is "six hundred sixty-seven million, six hundred thirty-eight thousand, two hundred forty-seven".