638822768640 has 1008 divisors, whose sum is σ = 2549986164432. Its totient is φ = 135687831552.

The previous prime is 638822768533. The next prime is 638822768641. The reversal of 638822768640 is 46867228836.

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 (638822768641) 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, 8086364121 + ... + 8086364199.

It is an arithmetic number, because the mean of its divisors is an integer number (2529748179).

Almost surely, 2^638822768640 is an apocalyptic number.

638822768640 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 638822768640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1274993082216).

638822768640 is an abundant number, since it is smaller than the sum of its proper divisors (1911163395792).

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

638822768640 is an equidigital number, since it uses as much as digits as its factorization.

638822768640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223 (or 113 counting only the distinct ones).

The product of its (nonzero) digits is 37158912, while the sum is 60.

The spelling of 638822768640 in words is "six hundred thirty-eight billion, eight hundred twenty-two million, seven hundred sixty-eight thousand, six hundred forty".