20720666064 has 120 divisors (see below), whose sum is σ = 62448607200. Its totient is φ = 5902993152.

The previous prime is 20720666027. The next prime is 20720666123. The reversal of 20720666064 is 46066602702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 808227 + ... + 833469.

It is an arithmetic number, because the mean of its divisors is an integer number (520405060).

Almost surely, 2^20720666064 is an apocalyptic number.

20720666064 is a gapful number since it is divisible by the number (24) 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 20720666064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31224303600).

20720666064 is an abundant number, since it is smaller than the sum of its proper divisors (41727941136).

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

20720666064 is a wasteful number, since it uses less digits than its factorization.

20720666064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25617 (or 25604 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 39.

The spelling of 20720666064 in words is "twenty billion, seven hundred twenty million, six hundred sixty-six thousand, sixty-four".