20121730720 has 384 divisors, whose sum is σ = 61622249472. Its totient is φ = 6038323200.

The previous prime is 20121730703. The next prime is 20121730751. The reversal of 20121730720 is 2703712102.

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, 22087065 + ... + 22087975.

It is an arithmetic number, because the mean of its divisors is an integer number (160474608).

Almost surely, 2^20121730720 is an apocalyptic number.

20121730720 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 20121730720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30811124736).

20121730720 is an abundant number, since it is smaller than the sum of its proper divisors (41500518752).

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

20121730720 is a wasteful number, since it uses less digits than its factorization.

20121730720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1024 (or 1016 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 25.

The spelling of 20121730720 in words is "twenty billion, one hundred twenty-one million, seven hundred thirty thousand, seven hundred twenty".