20665211776 has 64 divisors (see below), whose sum is σ = 45037814400. Its totient is φ = 9366883840.

The previous prime is 20665211773. The next prime is 20665211797. The reversal of 20665211776 is 67711256602.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20665211773) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 485031 + ... + 525913.

It is an arithmetic number, because the mean of its divisors is an integer number (703715850).

Almost surely, 2^20665211776 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20665211776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22518907200).

20665211776 is an abundant number, since it is smaller than the sum of its proper divisors (24372602624).

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

20665211776 is a wasteful number, since it uses less digits than its factorization.

20665211776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41267 (or 41255 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 43.

The spelling of 20665211776 in words is "twenty billion, six hundred sixty-five million, two hundred eleven thousand, seven hundred seventy-six".