21931226353920 has 288 divisors, whose sum is σ = 75437967128832. Its totient is φ = 5397940371456.

The previous prime is 21931226353909. The next prime is 21931226353963. The reversal of 21931226353920 is 2935362213912.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21931226353920.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1014713034 + ... + 1014734646.

It is an arithmetic number, because the mean of its divisors is an integer number (261937385864).

Almost surely, 2^{21931226353920} is an apocalyptic number.

21931226353920 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 21931226353920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37718983564416).

21931226353920 is an abundant number, since it is smaller than the sum of its proper divisors (53506740774912).

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

21931226353920 is a wasteful number, since it uses less digits than its factorization.

21931226353920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41977 (or 41963 counting only the distinct ones).

The product of its (nonzero) digits is 1049760, while the sum is 48.

The spelling of 21931226353920 in words is "twenty-one trillion, nine hundred thirty-one billion, two hundred twenty-six million, three hundred fifty-three thousand, nine hundred twenty".