21220873440 has 384 divisors, whose sum is σ = 74711185920. Its totient is φ = 5029060608.

The previous prime is 21220873367. The next prime is 21220873523. The reversal of 21220873440 is 4437802212.

It is a happy number.

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 63 ways as a sum of consecutive naturals, for example, 24703731 + ... + 24704589.

It is an arithmetic number, because the mean of its divisors is an integer number (194560380).

Almost surely, 2^21220873440 is an apocalyptic number.

21220873440 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 21220873440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37355592960).

21220873440 is an abundant number, since it is smaller than the sum of its proper divisors (53490312480).

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

21220873440 is a wasteful number, since it uses less digits than its factorization.

21220873440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1034 (or 1026 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 33.

The spelling of 21220873440 in words is "twenty-one billion, two hundred twenty million, eight hundred seventy-three thousand, four hundred forty".