21835505664 has 336 divisors, whose sum is σ = 74805040128. Its totient is φ = 6234734592.

The previous prime is 21835505663. The next prime is 21835505683. The reversal of 21835505664 is 46650553812.

21835505664 is a `hidden beast` number, since 2 + 1 + 8 + 35 + 50 + 566 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (336).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21835505663) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13933809 + ... + 13935375.

It is an arithmetic number, because the mean of its divisors is an integer number (222634048).

Almost surely, 2^21835505664 is an apocalyptic number.

21835505664 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 21835505664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37402520064).

21835505664 is an abundant number, since it is smaller than the sum of its proper divisors (52969534464).

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

21835505664 is an frugal number, since it uses more digits than its factorization.

21835505664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1615 (or 1579 counting only the distinct ones).

The product of its (nonzero) digits is 864000, while the sum is 45.

The spelling of 21835505664 in words is "twenty-one billion, eight hundred thirty-five million, five hundred five thousand, six hundred sixty-four".