20917185872 has 80 divisors (see below), whose sum is σ = 46221363072. Its totient is φ = 9077122560.

The previous prime is 20917185833. The next prime is 20917185901. The reversal of 20917185872 is 27858171902.

It is a self number, because there is not a number n which added to its sum of digits gives 20917185872.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2250098 + ... + 2259374.

Almost surely, 2^20917185872 is an apocalyptic number.

20917185872 is a gapful number since it is divisible by the number (22) 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 20917185872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23110681536).

20917185872 is an abundant number, since it is smaller than the sum of its proper divisors (25304177200).

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

20917185872 is a wasteful number, since it uses less digits than its factorization.

20917185872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9876 (or 9870 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 50.

The spelling of 20917185872 in words is "twenty billion, nine hundred seventeen million, one hundred eighty-five thousand, eight hundred seventy-two".