21805757952 has 320 divisors, whose sum is σ = 66184335360. Its totient is φ = 6319308800.

The previous prime is 21805757851. The next prime is 21805758031. The reversal of 21805757952 is 25975750812.

It is a super-2 number, since 2×21805757952² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21805757895 and 21805757904.

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, 93586828 + ... + 93587060.

It is an arithmetic number, because the mean of its divisors is an integer number (206826048).

Almost surely, 2^21805757952 is an apocalyptic number.

21805757952 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 21805757952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33092167680).

21805757952 is an abundant number, since it is smaller than the sum of its proper divisors (44378577408).

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

21805757952 is a wasteful number, since it uses less digits than its factorization.

21805757952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 485 (or 469 counting only the distinct ones).

The product of its (nonzero) digits is 1764000, while the sum is 51.

The spelling of 21805757952 in words is "twenty-one billion, eight hundred five million, seven hundred fifty-seven thousand, nine hundred fifty-two".