21805465344 has 144 divisors (see below), whose sum is σ = 66175415712. Its totient is φ = 6314655744.

The previous prime is 21805465333. The next prime is 21805465351. The reversal of 21805465344 is 44356450812.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21805465296 and 21805465305.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 105492 + ... + 233964.

It is an arithmetic number, because the mean of its divisors is an integer number (459551498).

Almost surely, 2^21805465344 is an apocalyptic number.

21805465344 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 21805465344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33087707856).

21805465344 is an abundant number, since it is smaller than the sum of its proper divisors (44369950368).

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

21805465344 is a wasteful number, since it uses less digits than its factorization.

21805465344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128522 (or 128508 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 42.

The spelling of 21805465344 in words is "twenty-one billion, eight hundred five million, four hundred sixty-five thousand, three hundred forty-four".