21200134400 has 108 divisors (see below), whose sum is σ = 53193634452. Its totient is φ = 8363704320.

The previous prime is 21200134363. The next prime is 21200134411. The reversal of 21200134400 is 443100212.

It can be written as a sum of positive squares in 6 ways, for example, as 135675904 + 21064458496 = 11648^2 + 145136^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 444512 + ... + 489888.

Almost surely, 2^21200134400 is an apocalyptic number.

21200134400 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 21200134400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26596817226).

21200134400 is an abundant number, since it is smaller than the sum of its proper divisors (31993500052).

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

21200134400 is an equidigital number, since it uses as much as digits as its factorization.

21200134400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45476 (or 45457 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

Adding to 21200134400 its reverse (443100212), we get a palindrome (21643234612).

The spelling of 21200134400 in words is "twenty-one billion, two hundred million, one hundred thirty-four thousand, four hundred".