21144333252 has 144 divisors (see below), whose sum is σ = 58261617792. Its totient is φ = 5844533760.

The previous prime is 21144333191. The next prime is 21144333307. The reversal of 21144333252 is 25233344112.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 27784552 + ... + 27785312.

It is an arithmetic number, because the mean of its divisors is an integer number (404594568).

Almost surely, 2^21144333252 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21144333252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29130808896).

21144333252 is an abundant number, since it is smaller than the sum of its proper divisors (37117284540).

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

21144333252 is a wasteful number, since it uses less digits than its factorization.

21144333252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 986 (or 905 counting only the distinct ones).

The product of its digits is 17280, while the sum is 30.

Adding to 21144333252 its reverse (25233344112), we get a palindrome (46377677364).

The spelling of 21144333252 in words is "twenty-one billion, one hundred forty-four million, three hundred thirty-three thousand, two hundred fifty-two".