21355122400000 has 216 divisors, whose sum is σ = 53333009906400. Its totient is φ = 8533570560000.

The previous prime is 21355122399971. The next prime is 21355122400019. The reversal of 21355122400000 is 422155312.

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

It is an unprimeable number.

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, 839187277 + ... + 839212723.

It is an arithmetic number, because the mean of its divisors is an integer number (246912082900).

Almost surely, 2^{21355122400000} is an apocalyptic number.

21355122400000 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 21355122400000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26666504953200).

21355122400000 is an abundant number, since it is smaller than the sum of its proper divisors (31977887506400).

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

21355122400000 is an frugal number, since it uses more digits than its factorization.

21355122400000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26537 (or 26503 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

Adding to 21355122400000 its reverse (422155312), we get a palindrome (21355544555312).

The spelling of 21355122400000 in words is "twenty-one trillion, three hundred fifty-five billion, one hundred twenty-two million, four hundred thousand".