21000220340440 has 256 divisors, whose sum is σ = 57119130547200. Its totient is φ = 6858735206400.

The previous prime is 21000220340431. The next prime is 21000220340527. The reversal of 21000220340440 is 4404302200012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 21244380 + ... + 22210900.

It is an arithmetic number, because the mean of its divisors is an integer number (223121603700).

Almost surely, 2^{21000220340440} is an apocalyptic number.

21000220340440 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 21000220340440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28559565273600).

21000220340440 is an abundant number, since it is smaller than the sum of its proper divisors (36118910206760).

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

21000220340440 is a wasteful number, since it uses less digits than its factorization.

21000220340440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 966698 (or 966694 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21000220340440 its reverse (4404302200012), we get a palindrome (25404522540452).

The spelling of 21000220340440 in words is "twenty-one trillion, two hundred twenty million, three hundred forty thousand, four hundred forty".