21421021344 has 96 divisors (see below), whose sum is σ = 59226370560. Its totient is φ = 6760339200.

The previous prime is 21421021333. The next prime is 21421021387. The reversal of 21421021344 is 44312012412.

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

It is a Harshad number since it is a multiple of its sum of digits (24).

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 15 ways as a sum of consecutive naturals, for example, 4395229 + ... + 4400099.

It is an arithmetic number, because the mean of its divisors is an integer number (616941360).

Almost surely, 2^21421021344 is an apocalyptic number.

21421021344 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 21421021344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29613185280).

21421021344 is an abundant number, since it is smaller than the sum of its proper divisors (37805349216).

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

21421021344 is a wasteful number, since it uses less digits than its factorization.

21421021344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7314 (or 7306 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 21421021344 its reverse (44312012412), we get a palindrome (65733033756).

The spelling of 21421021344 in words is "twenty-one billion, four hundred twenty-one million, twenty-one thousand, three hundred forty-four".