21220233144 has 128 divisors (see below), whose sum is σ = 61031577600. Its totient is φ = 6080711040.

The previous prime is 21220233137. The next prime is 21220233161. The reversal of 21220233144 is 44133202212.

It is a happy number.

It is a super-2 number, since 2×21220233144² (a number of 21 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2940789 + ... + 2947995.

It is an arithmetic number, because the mean of its divisors is an integer number (476809200).

Almost surely, 2^21220233144 is an apocalyptic number.

21220233144 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 21220233144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30515788800).

21220233144 is an abundant number, since it is smaller than the sum of its proper divisors (39811344456).

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

21220233144 is a wasteful number, since it uses less digits than its factorization.

21220233144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7833 (or 7829 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 21220233144 its reverse (44133202212), we get a palindrome (65353435356).

The spelling of 21220233144 in words is "twenty-one billion, two hundred twenty million, two hundred thirty-three thousand, one hundred forty-four".