638241421440 has 512 divisors, whose sum is σ = 2476960819200. Its totient is φ = 136535998464.

The previous prime is 638241421409. The next prime is 638241421553. The reversal of 638241421440 is 44124142836.

It is a super-2 number, since 2×638241421440² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 21179824 + ... + 21209936.

It is an arithmetic number, because the mean of its divisors is an integer number (4837814100).

Almost surely, 2^638241421440 is an apocalyptic number.

638241421440 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 638241421440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1238480409600).

638241421440 is an abundant number, since it is smaller than the sum of its proper divisors (1838719397760).

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

638241421440 is a wasteful number, since it uses less digits than its factorization.

638241421440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30244 (or 30232 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 39.

The spelling of 638241421440 in words is "six hundred thirty-eight billion, two hundred forty-one million, four hundred twenty-one thousand, four hundred forty".