20505709752 has 128 divisors (see below), whose sum is σ = 57669615360. Its totient is φ = 6022814720.

The previous prime is 20505709747. The next prime is 20505709771. The reversal of 20505709752 is 25790750502.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1152508 + ... + 1170164.

It is an arithmetic number, because the mean of its divisors is an integer number (450543870).

Almost surely, 2^20505709752 is an apocalyptic number.

20505709752 is a gapful number since it is divisible by the number (22) 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 20505709752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28834807680).

20505709752 is an abundant number, since it is smaller than the sum of its proper divisors (37163905608).

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

20505709752 is a wasteful number, since it uses less digits than its factorization.

20505709752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17813 (or 17809 counting only the distinct ones).

The product of its (nonzero) digits is 220500, while the sum is 42.

The spelling of 20505709752 in words is "twenty billion, five hundred five million, seven hundred nine thousand, seven hundred fifty-two".