21324144400 has 120 divisors (see below), whose sum is σ = 56346643584. Its totient is φ = 7705920000.

The previous prime is 21324144397. The next prime is 21324144419. The reversal of 21324144400 is 444142312.

It is a Harshad number since it is a multiple of its sum of digits (25).

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, 200775 + ... + 288025.

Almost surely, 2^21324144400 is an apocalyptic number.

21324144400 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 21324144400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28173321792).

21324144400 is an abundant number, since it is smaller than the sum of its proper divisors (35022499184).

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

21324144400 is a wasteful number, since it uses less digits than its factorization.

21324144400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87329 (or 87318 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 25.

Adding to 21324144400 its reverse (444142312), we get a palindrome (21768286712).

The spelling of 21324144400 in words is "twenty-one billion, three hundred twenty-four million, one hundred forty-four thousand, four hundred".