20984517664 has 96 divisors (see below), whose sum is σ = 48884617152. Its totient is φ = 8758272000.

The previous prime is 20984517641. The next prime is 20984517683. The reversal of 20984517664 is 46671548902.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 202579 + ... + 288109.

It is an arithmetic number, because the mean of its divisors is an integer number (509214762).

Almost surely, 2^20984517664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20984517664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24442308576).

20984517664 is an abundant number, since it is smaller than the sum of its proper divisors (27900099488).

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

20984517664 is a wasteful number, since it uses less digits than its factorization.

20984517664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85610 (or 85602 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 52.

The spelling of 20984517664 in words is "twenty billion, nine hundred eighty-four million, five hundred seventeen thousand, six hundred sixty-four".