638055900 has 144 divisors (see below), whose sum is σ = 2172048480. Its totient is φ = 160128000.

The previous prime is 638055893. The next prime is 638055907. The reversal of 638055900 is 9550836.

638055900 is a `hidden beast` number, since 63 + 8 + 0 + 5 + 590 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (638055893) and next prime (638055907).

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 (638055907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 38950 + ... + 52850.

It is an arithmetic number, because the mean of its divisors is an integer number (15083670).

Almost surely, 2^638055900 is an apocalyptic number.

638055900 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 638055900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1086024240).

638055900 is an abundant number, since it is smaller than the sum of its proper divisors (1533992580).

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

638055900 is a wasteful number, since it uses less digits than its factorization.

638055900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13941 (or 13928 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 638055900 is about 25259.7684074894. The cubic root of 638055900 is about 860.9004000414.

The spelling of 638055900 in words is "six hundred thirty-eight million, fifty-five thousand, nine hundred".