638313660 has 72 divisors (see below), whose sum is σ = 1955073120. Its totient is φ = 168559488.

The previous prime is 638313659. The next prime is 638313661. The reversal of 638313660 is 66313836.

638313660 is a `hidden beast` number, since 638 + 3 + 13 + 6 + 6 + 0 = 666.

638313660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (638313659) and next prime (638313661).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638313661) 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, 1326 + ... + 35754.

Almost surely, 2^638313660 is an apocalyptic number.

638313660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638313660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (977536560).

638313660 is an abundant number, since it is smaller than the sum of its proper divisors (1316759460).

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

638313660 is a wasteful number, since it uses less digits than its factorization.

638313660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34547 (or 34542 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 36.

The square root of 638313660 is about 25264.8700768478. The cubic root of 638313660 is about 861.0163124623.

The spelling of 638313660 in words is "six hundred thirty-eight million, three hundred thirteen thousand, six hundred sixty".