21121322144 has 48 divisors (see below), whose sum is σ = 44978740128. Its totient is φ = 9705315072.

The previous prime is 21121322143. The next prime is 21121322191. The reversal of 21121322144 is 44122312112.

It is a super-2 number, since 2×21121322144² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121322141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17402 + ... + 206265.

It is an arithmetic number, because the mean of its divisors is an integer number (937057086).

Almost surely, 2^21121322144 is an apocalyptic number.

It is an amenable number.

21121322144 is an abundant number, since it is smaller than the sum of its proper divisors (23857417984).

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

21121322144 is a wasteful number, since it uses less digits than its factorization.

21121322144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223917 (or 223909 counting only the distinct ones).

The product of its digits is 768, while the sum is 23.

Adding to 21121322144 its reverse (44122312112), we get a palindrome (65243634256).

The spelling of 21121322144 in words is "twenty-one billion, one hundred twenty-one million, three hundred twenty-two thousand, one hundred forty-four".