21531533300400 has 240 divisors, whose sum is σ = 70202296194048. Its totient is φ = 5639977728000.

The previous prime is 21531533300393. The next prime is 21531533300419. The reversal of 21531533300400 is 400333513512.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22622932 + ... + 23555468.

Almost surely, 2^{21531533300400} is an apocalyptic number.

21531533300400 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 21531533300400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35101148097024).

21531533300400 is an abundant number, since it is smaller than the sum of its proper divisors (48670762893648).

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

21531533300400 is a wasteful number, since it uses less digits than its factorization.

21531533300400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 932900 (or 932889 counting only the distinct ones).

The product of its (nonzero) digits is 16200, while the sum is 30.

Adding to 21531533300400 its reverse (400333513512), we get a palindrome (21931866813912).

The spelling of 21531533300400 in words is "twenty-one trillion, five hundred thirty-one billion, five hundred thirty-three million, three hundred thousand, four hundred".