638622497940 has 288 divisors, whose sum is σ = 2127019345920. Its totient is φ = 140233524480.

The previous prime is 638622497911. The next prime is 638622497941. The reversal of 638622497940 is 49794226836.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638622497941) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 56097489 + ... + 56108871.

It is an arithmetic number, because the mean of its divisors is an integer number (7385483840).

Almost surely, 2^638622497940 is an apocalyptic number.

638622497940 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 638622497940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1063509672960).

638622497940 is an abundant number, since it is smaller than the sum of its proper divisors (1488396847980).

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

638622497940 is a wasteful number, since it uses less digits than its factorization.

638622497940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11603 (or 11570 counting only the distinct ones).

The product of its (nonzero) digits is 31352832, while the sum is 60.

The spelling of 638622497940 in words is "six hundred thirty-eight billion, six hundred twenty-two million, four hundred ninety-seven thousand, nine hundred forty".