638137812 has 48 divisors (see below), whose sum is σ = 1610618240. Its totient is φ = 195481728.

The previous prime is 638137807. The next prime is 638137873. The reversal of 638137812 is 218731836.

It is a Harshad number since it is a multiple of its sum of digits (39).

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 15 ways as a sum of consecutive naturals, for example, 26793 + ... + 44655.

Almost surely, 2^638137812 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 638137812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (805309120).

638137812 is an abundant number, since it is smaller than the sum of its proper divisors (972480428).

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

638137812 is a wasteful number, since it uses less digits than its factorization.

638137812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18112 (or 18110 counting only the distinct ones).

The product of its digits is 48384, while the sum is 39.

The square root of 638137812 is about 25261.3897479929. The cubic root of 638137812 is about 860.9372385358.

The spelling of 638137812 in words is "six hundred thirty-eight million, one hundred thirty-seven thousand, eight hundred twelve".