638941680 has 360 divisors, whose sum is σ = 2389467600. Its totient is φ = 152875008.

The previous prime is 638941673. The next prime is 638941691. The reversal of 638941680 is 86149836.

638941680 is a `hidden beast` number, since 638 + 9 + 4 + 1 + 6 + 8 + 0 = 666.

638941680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (360).

It is a super-3 number, since 3×638941680³ (a number of 27 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (45) 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 (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 7179076 + ... + 7179164.

It is an arithmetic number, because the mean of its divisors is an integer number (6637410).

Almost surely, 2^638941680 is an apocalyptic number.

638941680 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 638941680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1194733800).

638941680 is an abundant number, since it is smaller than the sum of its proper divisors (1750525920).

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

638941680 is a wasteful number, since it uses less digits than its factorization.

638941680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193 (or 171 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 638941680 is about 25277.2957414356. The cubic root of 638941680 is about 861.2985969967.

The spelling of 638941680 in words is "six hundred thirty-eight million, nine hundred forty-one thousand, six hundred eighty".