638940960 has 240 divisors, whose sum is σ = 2577427776. Its totient is φ = 146022912.

The previous prime is 638940959. The next prime is 638940961. The reversal of 638940960 is 69049836.

638940960 is a `hidden beast` number, since 638 + 9 + 4 + 0 + 9 + 6 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (638940959) and next prime (638940961).

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (638940961) by changing a digit.

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 39 ways as a sum of consecutive naturals, for example, 87199 + ... + 94241.

Almost surely, 2^638940960 is an apocalyptic number.

638940960 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 638940960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1288713888).

638940960 is an abundant number, since it is smaller than the sum of its proper divisors (1938486816).

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

638940960 is a wasteful number, since it uses less digits than its factorization.

638940960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7077 (or 7060 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The square root of 638940960 is about 25277.2814994018. The cubic root of 638940960 is about 861.2982734747.

The spelling of 638940960 in words is "six hundred thirty-eight million, nine hundred forty thousand, nine hundred sixty".