21801858560 has 240 divisors, whose sum is σ = 57023885952. Its totient is φ = 7984742400.

The previous prime is 21801858511. The next prime is 21801858563. The reversal of 21801858560 is 6585810812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21801858563) 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 23 ways as a sum of consecutive naturals, for example, 28648580 + ... + 28649340.

Almost surely, 2^21801858560 is an apocalyptic number.

21801858560 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 21801858560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28511942976).

21801858560 is an abundant number, since it is smaller than the sum of its proper divisors (35222027392).

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

21801858560 is an equidigital number, since it uses as much as digits as its factorization.

21801858560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 853 (or 818 counting only the distinct ones).

The product of its (nonzero) digits is 153600, while the sum is 44.

The spelling of 21801858560 in words is "twenty-one billion, eight hundred one million, eight hundred fifty-eight thousand, five hundred sixty".