20865679956 has 108 divisors (see below), whose sum is σ = 58059301300. Its totient is φ = 6313697280.

The previous prime is 20865679931. The next prime is 20865679957. The reversal of 20865679956 is 65997656802.

It can be written as a sum of positive squares in 2 ways, for example, as 9348956100 + 11516723856 = 96690^2 + 107316^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20865679893 and 20865679902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20865679957) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3346650 + ... + 3352878.

Almost surely, 2^20865679956 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 20865679956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29029650650).

20865679956 is an abundant number, since it is smaller than the sum of its proper divisors (37193621344).

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

20865679956 is a wasteful number, since it uses less digits than its factorization.

20865679956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7030 (or 7014 counting only the distinct ones).

The product of its (nonzero) digits is 48988800, while the sum is 63.

The spelling of 20865679956 in words is "twenty billion, eight hundred sixty-five million, six hundred seventy-nine thousand, nine hundred fifty-six".