20866916905128 has 320 divisors, whose sum is σ = 68450466268800. Its totient is φ = 5814430801920.

The previous prime is 20866916905127. The next prime is 20866916905129. The reversal of 20866916905128 is 82150961966802.

20866916905128 is a `hidden beast` number, since 20 + 8 + 6 + 6 + 9 + 1 + 6 + 90 + 512 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (20866916905127) and next prime (20866916905129).

It is a super-2 number, since 2×20866916905128² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (20866916905127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 546564376 + ... + 546602552.

It is an arithmetic number, because the mean of its divisors is an integer number (213907707090).

Almost surely, 2^{20866916905128} is an apocalyptic number.

20866916905128 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 20866916905128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34225233134400).

20866916905128 is an abundant number, since it is smaller than the sum of its proper divisors (47583549363672).

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

20866916905128 is a wasteful number, since it uses less digits than its factorization.

20866916905128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41182 (or 41169 counting only the distinct ones).

The product of its (nonzero) digits is 22394880, while the sum is 63.

The spelling of 20866916905128 in words is "twenty trillion, eight hundred sixty-six billion, nine hundred sixteen million, nine hundred five thousand, one hundred twenty-eight".