21225421344 has 96 divisors (see below), whose sum is σ = 57453084864. Its totient is φ = 6857876480.

The previous prime is 21225421339. The next prime is 21225421363. The reversal of 21225421344 is 44312452212.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×21225421344² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 397174 + ... + 447434.

It is an arithmetic number, because the mean of its divisors is an integer number (598469634).

Almost surely, 2^21225421344 is an apocalyptic number.

21225421344 is a gapful number since it is divisible by the number (24) 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 21225421344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28726542432).

21225421344 is an abundant number, since it is smaller than the sum of its proper divisors (36227663520).

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

21225421344 is a wasteful number, since it uses less digits than its factorization.

21225421344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50410 (or 50402 counting only the distinct ones).

The product of its digits is 15360, while the sum is 30.

Adding to 21225421344 its reverse (44312452212), we get a palindrome (65537873556).

The spelling of 21225421344 in words is "twenty-one billion, two hundred twenty-five million, four hundred twenty-one thousand, three hundred forty-four".