21202005440 has 224 divisors, whose sum is σ = 63082188288. Its totient is φ = 6594048000.

The previous prime is 21202005427. The next prime is 21202005443. The reversal of 21202005440 is 4450020212.

It is a happy number.

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 (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202005443) 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, 19982510 + ... + 19983570.

It is an arithmetic number, because the mean of its divisors is an integer number (281616912).

Almost surely, 2^21202005440 is an apocalyptic number.

21202005440 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 21202005440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31541094144).

21202005440 is an abundant number, since it is smaller than the sum of its proper divisors (41880182848).

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

21202005440 is a wasteful number, since it uses less digits than its factorization.

21202005440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1907 (or 1897 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

Adding to 21202005440 its reverse (4450020212), we get a palindrome (25652025652).

The spelling of 21202005440 in words is "twenty-one billion, two hundred two million, five thousand, four hundred forty".