21243001440 has 192 divisors, whose sum is σ = 71162110656. Its totient is φ = 5308219392.

The previous prime is 21243001369. The next prime is 21243001453. The reversal of 21243001440 is 4410034212.

It is a super-2 number, since 2×21243001440² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 1895694 + ... + 1906866.

It is an arithmetic number, because the mean of its divisors is an integer number (370635993).

Almost surely, 2^21243001440 is an apocalyptic number.

21243001440 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 21243001440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35581055328).

21243001440 is an abundant number, since it is smaller than the sum of its proper divisors (49919109216).

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

21243001440 is a wasteful number, since it uses less digits than its factorization.

21243001440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11441 (or 11433 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

Adding to 21243001440 its reverse (4410034212), we get a palindrome (25653035652).

The spelling of 21243001440 in words is "twenty-one billion, two hundred forty-three million, one thousand, four hundred forty".