667885638 has 64 divisors (see below), whose sum is σ = 1644429312. Its totient is φ = 176631840.

The previous prime is 667885609. The next prime is 667885639. The reversal of 667885638 is 836588766.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667885639) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18795 + ... + 41097.

It is an arithmetic number, because the mean of its divisors is an integer number (25694208).

Almost surely, 2^667885638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 667885638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (822214656).

667885638 is an abundant number, since it is smaller than the sum of its proper divisors (976543674).

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

667885638 is a wasteful number, since it uses less digits than its factorization.

667885638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22369.

The product of its digits is 11612160, while the sum is 57.

The square root of 667885638 is about 25843.4834726281. The cubic root of 667885638 is about 874.1125753261.

The spelling of 667885638 in words is "six hundred sixty-seven million, eight hundred eighty-five thousand, six hundred thirty-eight".