638443800 has 216 divisors, whose sum is σ = 2208093420. Its totient is φ = 165312000.

The previous prime is 638443781. The next prime is 638443801. The reversal of 638443800 is 8344836.

It is a super-2 number, since 2×638443800² = 815220971516880000, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638443801) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 3025695 + ... + 3025905.

Almost surely, 2^638443800 is an apocalyptic number.

638443800 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 638443800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1104046710).

638443800 is an abundant number, since it is smaller than the sum of its proper divisors (1569649620).

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

638443800 is a wasteful number, since it uses less digits than its factorization.

638443800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315 (or 262 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 638443800 is about 25267.4454585342. The cubic root of 638443800 is about 861.0748234294.

The spelling of 638443800 in words is "six hundred thirty-eight million, four hundred forty-three thousand, eight hundred".