21223144400 has 120 divisors (see below), whose sum is σ = 54553279200. Its totient is φ = 7910438400.

The previous prime is 21223144387. The next prime is 21223144421. The reversal of 21223144400 is 444132212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 440711 + ... + 486489.

It is an arithmetic number, because the mean of its divisors is an integer number (454610660).

Almost surely, 2^21223144400 is an apocalyptic number.

21223144400 is a gapful number since it is divisible by the number (20) 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 21223144400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27276639600).

21223144400 is an abundant number, since it is smaller than the sum of its proper divisors (33330134800).

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

21223144400 is a wasteful number, since it uses less digits than its factorization.

21223144400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45877 (or 45866 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21223144400 its reverse (444132212), we get a palindrome (21667276612).

The spelling of 21223144400 in words is "twenty-one billion, two hundred twenty-three million, one hundred forty-four thousand, four hundred".