20856336540 has 192 divisors, whose sum is σ = 64418457600. Its totient is φ = 5010610176.

The previous prime is 20856336517. The next prime is 20856336541. The reversal of 20856336540 is 4563365802.

It is a junction number, because it is equal to n+sod(n) for n = 20856336492 and 20856336501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20856336541) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5482279 + ... + 5486081.

It is an arithmetic number, because the mean of its divisors is an integer number (335512800).

Almost surely, 2^20856336540 is an apocalyptic number.

20856336540 is a gapful number since it is divisible by the number (20) 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 20856336540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32209228800).

20856336540 is an abundant number, since it is smaller than the sum of its proper divisors (43562121060).

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

20856336540 is a wasteful number, since it uses less digits than its factorization.

20856336540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3996 (or 3994 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 42.

The spelling of 20856336540 in words is "twenty billion, eight hundred fifty-six million, three hundred thirty-six thousand, five hundred forty".