21221343400 has 96 divisors (see below), whose sum is σ = 50090544000. Its totient is φ = 8359902720.

The previous prime is 21221343397. The next prime is 21221343413. The reversal of 21221343400 is 434312212.

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, 7219131 + ... + 7222069.

It is an arithmetic number, because the mean of its divisors is an integer number (521776500).

Almost surely, 2^21221343400 is an apocalyptic number.

21221343400 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 21221343400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25045272000).

21221343400 is an abundant number, since it is smaller than the sum of its proper divisors (28869200600).

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

21221343400 is a wasteful number, since it uses less digits than its factorization.

21221343400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3491 (or 3482 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

Adding to 21221343400 its reverse (434312212), we get a palindrome (21655655612).

The spelling of 21221343400 in words is "twenty-one billion, two hundred twenty-one million, three hundred forty-three thousand, four hundred".