20645949768 has 64 divisors (see below), whose sum is σ = 53273376000. Its totient is φ = 6664333632.

The previous prime is 20645949767. The next prime is 20645949809. The reversal of 20645949768 is 86794954602.

It is not an unprimeable number, because it can be changed into a prime (20645949767) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13938 + ... + 203681.

It is an arithmetic number, because the mean of its divisors is an integer number (832396500).

Almost surely, 2^20645949768 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 20645949768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26636688000).

20645949768 is an abundant number, since it is smaller than the sum of its proper divisors (32627426232).

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

20645949768 is a wasteful number, since it uses less digits than its factorization.

20645949768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217754 (or 217750 counting only the distinct ones).

The product of its (nonzero) digits is 26127360, while the sum is 60.

The spelling of 20645949768 in words is "twenty billion, six hundred forty-five million, nine hundred forty-nine thousand, seven hundred sixty-eight".