21721943040 has 880 divisors, whose sum is σ = 88068817920. Its totient is φ = 4551966720.

The previous prime is 21721943039. The next prime is 21721943083. The reversal of 21721943040 is 4034912712.

It is a junction number, because it is equal to n+sod(n) for n = 21721942992 and 21721943010.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 700707825 + ... + 700707855.

Almost surely, 2^21721943040 is an apocalyptic number.

21721943040 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 21721943040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44034408960).

21721943040 is an abundant number, since it is smaller than the sum of its proper divisors (66346874880).

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

21721943040 is an equidigital number, since it uses as much as digits as its factorization.

21721943040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The spelling of 21721943040 in words is "twenty-one billion, seven hundred twenty-one million, nine hundred forty-three thousand, forty".