638440560 has 120 divisors (see below), whose sum is σ = 2149602000. Its totient is φ = 169814016.

The previous prime is 638440547. The next prime is 638440609. The reversal of 638440560 is 65044836.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×638440560² = 815212697306227200, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 358392 + ... + 360168.

It is an arithmetic number, because the mean of its divisors is an integer number (17913350).

Almost surely, 2^638440560 is an apocalyptic number.

638440560 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 638440560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1074801000).

638440560 is an abundant number, since it is smaller than the sum of its proper divisors (1511161440).

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

638440560 is a wasteful number, since it uses less digits than its factorization.

638440560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2295 (or 2286 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The square root of 638440560 is about 25267.3813443340. The cubic root of 638440560 is about 861.0733668214.

The spelling of 638440560 in words is "six hundred thirty-eight million, four hundred forty thousand, five hundred sixty".