21212454444 has 96 divisors (see below), whose sum is σ = 54066216960. Its totient is φ = 6452846400.

The previous prime is 21212454437. The next prime is 21212454451. The reversal of 21212454444 is 44445421212.

It is an interprime number because it is at equal distance from previous prime (21212454437) and next prime (21212454451).

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 31 ways as a sum of consecutive naturals, for example, 590017 + ... + 624935.

It is an arithmetic number, because the mean of its divisors is an integer number (563189760).

Almost surely, 2^21212454444 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 21212454444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27033108480).

21212454444 is an abundant number, since it is smaller than the sum of its proper divisors (32853762516).

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

21212454444 is a wasteful number, since it uses less digits than its factorization.

21212454444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35051 (or 35049 counting only the distinct ones).

The product of its digits is 40960, while the sum is 33.

Adding to 21212454444 its reverse (44445421212), we get a palindrome (65657875656).

The spelling of 21212454444 in words is "twenty-one billion, two hundred twelve million, four hundred fifty-four thousand, four hundred forty-four".