667636640 has 96 divisors (see below), whose sum is σ = 1795602816. Its totient is φ = 232207360.

The previous prime is 667636639. The next prime is 667636679. The reversal of 667636640 is 46636766.

667636640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 667636591 and 667636600.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32234 + ... + 48726.

It is an arithmetic number, because the mean of its divisors is an integer number (18704196).

Almost surely, 2^667636640 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 667636640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (897801408).

667636640 is an abundant number, since it is smaller than the sum of its proper divisors (1127966176).

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

667636640 is a wasteful number, since it uses less digits than its factorization.

667636640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16542 (or 16534 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 44.

The square root of 667636640 is about 25838.6656002201. The cubic root of 667636640 is about 874.0039343032.

The spelling of 667636640 in words is "six hundred sixty-seven million, six hundred thirty-six thousand, six hundred forty".