638423985600 has 504 divisors, whose sum is σ = 2477029376640. Its totient is φ = 161284193280.

The previous prime is 638423985569. The next prime is 638423985607. The reversal of 638423985600 is 6589324836.

638423985600 is a `hidden beast` number, since 6 + 3 + 8 + 4 + 23 + 9 + 8 + 5 + 600 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638423985607) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 7343989 + ... + 7430411.

Almost surely, 2^638423985600 is an apocalyptic number.

638423985600 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 638423985600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1238514688320).

638423985600 is an abundant number, since it is smaller than the sum of its proper divisors (1838605391040).

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

638423985600 is a wasteful number, since it uses less digits than its factorization.

638423985600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86479 (or 86452 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 54.

The spelling of 638423985600 in words is "six hundred thirty-eight billion, four hundred twenty-three million, nine hundred eighty-five thousand, six hundred".