20721920000 has 120 divisors (see below), whose sum is σ = 51778777050. Its totient is φ = 8288256000.

The previous prime is 20721919963. The next prime is 20721920069. The reversal of 20721920000 is 2912702.

It can be written as a sum of positive squares in 5 ways, for example, as 197346304 + 20524573696 = 14048^2 + 143264^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1271906 + ... + 1288094.

Almost surely, 2^20721920000 is an apocalyptic number.

20721920000 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 20721920000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25889388525).

20721920000 is an abundant number, since it is smaller than the sum of its proper divisors (31056857050).

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

20721920000 is an frugal number, since it uses more digits than its factorization.

20721920000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16231 (or 16196 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 23.

The spelling of 20721920000 in words is "twenty billion, seven hundred twenty-one million, nine hundred twenty thousand".