20571917688 has 192 divisors, whose sum is σ = 67997030400. Its totient is φ = 5491825920.

The previous prime is 20571917683. The next prime is 20571917693. The reversal of 20571917688 is 88671917502.

20571917688 is a `hidden beast` number, since 2 + 0 + 571 + 9 + 1 + 7 + 68 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (20571917683) and next prime (20571917693).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20571917683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 430395 + ... + 475797.

It is an arithmetic number, because the mean of its divisors is an integer number (354151200).

Almost surely, 2^20571917688 is an apocalyptic number.

20571917688 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 20571917688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33998515200).

20571917688 is an abundant number, since it is smaller than the sum of its proper divisors (47425112712).

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

20571917688 is a wasteful number, since it uses less digits than its factorization.

20571917688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45482 (or 45475 counting only the distinct ones).

The product of its (nonzero) digits is 1693440, while the sum is 54.

The spelling of 20571917688 in words is "twenty billion, five hundred seventy-one million, nine hundred seventeen thousand, six hundred eighty-eight".