638741740 has 96 divisors (see below), whose sum is σ = 1722792960. Its totient is φ = 193349376.

The previous prime is 638741723. The next prime is 638741749. The reversal of 638741740 is 47147836.

It is a junction number, because it is equal to n+sod(n) for n = 638741693 and 638741702.

It is not an unprimeable number, because it can be changed into a prime (638741749) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34231 + ... + 49489.

It is an arithmetic number, because the mean of its divisors is an integer number (17945760).

Almost surely, 2^638741740 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638741740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (861396480).

638741740 is an abundant number, since it is smaller than the sum of its proper divisors (1084051220).

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

638741740 is a wasteful number, since it uses less digits than its factorization.

638741740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15311 (or 15309 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 40.

The square root of 638741740 is about 25273.3404994275. The cubic root of 638741740 is about 861.2087473737.

The spelling of 638741740 in words is "six hundred thirty-eight million, seven hundred forty-one thousand, seven hundred forty".