667634688 has 264 divisors, whose sum is σ = 2248097280. Its totient is φ = 186900480.

The previous prime is 667634687. The next prime is 667634717. The reversal of 667634688 is 886436766.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

Its product of digits (6967296) is a multiple of the sum of its prime factors (243).

It is not an unprimeable number, because it can be changed into a prime (667634683) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5096383 + ... + 5096513.

It is an arithmetic number, because the mean of its divisors is an integer number (8515520).

Almost surely, 2^667634688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 667634688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1124048640).

667634688 is an abundant number, since it is smaller than the sum of its proper divisors (1580462592).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

667634688 is a wasteful number, since it uses less digits than its factorization.

667634688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243 (or 222 counting only the distinct ones).

The product of its digits is 6967296, while the sum is 54.

The square root of 667634688 is about 25838.6278273441. The cubic root of 667634688 is about 874.0030825139.

The spelling of 667634688 in words is "six hundred sixty-seven million, six hundred thirty-four thousand, six hundred eighty-eight".