20915766778368 has 480 divisors, whose sum is σ = 70980366251520. Its totient is φ = 5411953827840.

The previous prime is 20915766778367. The next prime is 20915766778373. The reversal of 20915766778368 is 86387766751902.

It is a self number, because there is not a number n which added to its sum of digits gives 20915766778368.

It is not an unprimeable number, because it can be changed into a prime (20915766778367) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 217690723 + ... + 217786781.

It is an arithmetic number, because the mean of its divisors is an integer number (147875763024).

Almost surely, 2^{20915766778368} is an apocalyptic number.

20915766778368 is a gapful number since it is divisible by the number (28) 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 20915766778368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35490183125760).

20915766778368 is an abundant number, since it is smaller than the sum of its proper divisors (50064599473152).

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

20915766778368 is a wasteful number, since it uses less digits than its factorization.

20915766778368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96368 (or 96345 counting only the distinct ones).

The product of its (nonzero) digits is 1280240640, while the sum is 75.

The spelling of 20915766778368 in words is "twenty trillion, nine hundred fifteen billion, seven hundred sixty-six million, seven hundred seventy-eight thousand, three hundred sixty-eight".