21035442400 has 144 divisors (see below), whose sum is σ = 58796236800. Its totient is φ = 7198963200.

The previous prime is 21035442377. The next prime is 21035442401. The reversal of 21035442400 is 424453012.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21035442401) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 3351265 + ... + 3357535.

It is an arithmetic number, because the mean of its divisors is an integer number (408307200).

Almost surely, 2^21035442400 is an apocalyptic number.

21035442400 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 21035442400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29398118400).

21035442400 is an abundant number, since it is smaller than the sum of its proper divisors (37760794400).

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

21035442400 is a wasteful number, since it uses less digits than its factorization.

21035442400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6897 (or 6884 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 25.

Adding to 21035442400 its reverse (424453012), we get a palindrome (21459895412).

The spelling of 21035442400 in words is "twenty-one billion, thirty-five million, four hundred forty-two thousand, four hundred".