20720394240 has 896 divisors, whose sum is σ = 87194257920. Its totient is φ = 4076863488.

The previous prime is 20720394199. The next prime is 20720394263. The reversal of 20720394240 is 4249302702.

It is a tau number, because it is divible by the number of its divisors (896).

It is a super-2 number, since 2×20720394240² (a number of 21 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, 190095306 + ... + 190095414.

It is an arithmetic number, because the mean of its divisors is an integer number (97315020).

Almost surely, 2^20720394240 is an apocalyptic number.

20720394240 is a gapful number since it is divisible by the number (20) 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 20720394240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43597128960).

20720394240 is an abundant number, since it is smaller than the sum of its proper divisors (66473863680).

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

20720394240 is a wasteful number, since it uses less digits than its factorization.

20720394240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180 (or 156 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 33.

Adding to 20720394240 its reverse (4249302702), we get a palindrome (24969696942).

The spelling of 20720394240 in words is "twenty billion, seven hundred twenty million, three hundred ninety-four thousand, two hundred forty".