21698517984 has 192 divisors, whose sum is σ = 68726568960. Its totient is φ = 5905336320.

The previous prime is 21698517977. The next prime is 21698518001. The reversal of 21698517984 is 48971589612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 486577 + ... + 529295.

It is an arithmetic number, because the mean of its divisors is an integer number (357950880).

Almost surely, 2^21698517984 is an apocalyptic number.

21698517984 is a gapful number since it is divisible by the number (24) 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 21698517984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34363284480).

21698517984 is an abundant number, since it is smaller than the sum of its proper divisors (47028050976).

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

21698517984 is a wasteful number, since it uses less digits than its factorization.

21698517984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42793 (or 42785 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 60.

The spelling of 21698517984 in words is "twenty-one billion, six hundred ninety-eight million, five hundred seventeen thousand, nine hundred eighty-four".