638132040 has 512 divisors, whose sum is σ = 2696601600. Its totient is φ = 130636800.

The previous prime is 638132021. The next prime is 638132069. The reversal of 638132040 is 40231836.

It is a happy number.

638132040 is a `hidden beast` number, since 638 + 1 + 3 + 20 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 638131995 and 638132013.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4225965 + ... + 4226115.

It is an arithmetic number, because the mean of its divisors is an integer number (5266800).

Almost surely, 2^638132040 is an apocalyptic number.

638132040 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 638132040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1348300800).

638132040 is an abundant number, since it is smaller than the sum of its proper divisors (2058469560).

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

638132040 is a wasteful number, since it uses less digits than its factorization.

638132040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234 (or 224 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 638132040 is about 25261.2755022386. The cubic root of 638132040 is about 860.9346427826.

Adding to 638132040 its reverse (40231836), we get a palindrome (678363876).

The spelling of 638132040 in words is "six hundred thirty-eight million, one hundred thirty-two thousand, forty".