21999823560 has 640 divisors, whose sum is σ = 87904776960. Its totient is φ = 4864665600.

The previous prime is 21999823553. The next prime is 21999823561. The reversal of 21999823560 is 6532899912.

It is a happy number.

It is a super-2 number, since 2×21999823560² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 21999823497 and 21999823506.

It is not an unprimeable number, because it can be changed into a prime (21999823561) by changing a digit.

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 159 ways as a sum of consecutive naturals, for example, 47721730 + ... + 47722190.

It is an arithmetic number, because the mean of its divisors is an integer number (137351214).

Almost surely, 2^21999823560 is an apocalyptic number.

21999823560 is a gapful number since it is divisible by the number (20) 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 21999823560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43952388480).

21999823560 is an abundant number, since it is smaller than the sum of its proper divisors (65904953400).

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

21999823560 is a wasteful number, since it uses less digits than its factorization.

21999823560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 611 (or 598 counting only the distinct ones).

The product of its (nonzero) digits is 2099520, while the sum is 54.

The spelling of 21999823560 in words is "twenty-one billion, nine hundred ninety-nine million, eight hundred twenty-three thousand, five hundred sixty".