638374338 has 128 divisors (see below), whose sum is σ = 1710858240. Its totient is φ = 172497600.

The previous prime is 638374337. The next prime is 638374339. The reversal of 638374338 is 833473836.

638374338 is a `hidden beast` number, since 638 + 3 + 7 + 4 + 3 + 3 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (638374337) and next prime (638374339).

It is a junction number, because it is equal to n+sod(n) for n = 638374293 and 638374302.

It is not an unprimeable number, because it can be changed into a prime (638374337) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 877731 + ... + 878457.

It is an arithmetic number, because the mean of its divisors is an integer number (13366080).

Almost surely, 2^638374338 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638374338, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (855429120).

638374338 is an abundant number, since it is smaller than the sum of its proper divisors (1072483902).

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

638374338 is a wasteful number, since it uses less digits than its factorization.

638374338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 869 (or 863 counting only the distinct ones).

The product of its digits is 870912, while the sum is 45.

The square root of 638374338 is about 25266.0708856759. The cubic root of 638374338 is about 861.0435942914.

The spelling of 638374338 in words is "six hundred thirty-eight million, three hundred seventy-four thousand, three hundred thirty-eight".