21024403400 has 288 divisors, whose sum is σ = 66135558720. Its totient is φ = 6048345600.

The previous prime is 21024403397. The next prime is 21024403409. The reversal of 21024403400 is 430442012.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21024403409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2197427 + ... + 2206973.

Almost surely, 2^21024403400 is an apocalyptic number.

21024403400 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 21024403400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33067779360).

21024403400 is an abundant number, since it is smaller than the sum of its proper divisors (45111155320).

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

21024403400 is a wasteful number, since it uses less digits than its factorization.

21024403400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9605 (or 9585 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

Adding to 21024403400 its reverse (430442012), we get a palindrome (21454845412).

It can be divided in two parts, 21024 and 403400, that added together give a palindrome (424424).

The spelling of 21024403400 in words is "twenty-one billion, twenty-four million, four hundred three thousand, four hundred".