21810210240 has 224 divisors, whose sum is σ = 85227932160. Its totient is φ = 4601696256.

The previous prime is 21810210209. The next prime is 21810210241. The reversal of 21810210240 is 4201201812.

It is a tau number, because it is divible by the number of its divisors (224).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21810210241) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37470 + ... + 212189.

It is an arithmetic number, because the mean of its divisors is an integer number (380481840).

Almost surely, 2^21810210240 is an apocalyptic number.

21810210240 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 21810210240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42613966080).

21810210240 is an abundant number, since it is smaller than the sum of its proper divisors (63417721920).

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

21810210240 is a wasteful number, since it uses less digits than its factorization.

21810210240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249699 (or 249689 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 21.

The spelling of 21810210240 in words is "twenty-one billion, eight hundred ten million, two hundred ten thousand, two hundred forty".