21655433134400 has 252 divisors, whose sum is σ = 59689797549300. Its totient is φ = 7720130396160.

The previous prime is 21655433134399. The next prime is 21655433134499. The reversal of 21655433134400 is 443133455612.

It is a happy number.

It can be written as a sum of positive squares in 18 ways, for example, as 21497614448704 + 157818685696 = 4636552^2 + 397264^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 6460796 + ... + 9222404.

Almost surely, 2^{21655433134400} is an apocalyptic number.

21655433134400 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 21655433134400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29844898774650).

21655433134400 is an abundant number, since it is smaller than the sum of its proper divisors (38034364414900).

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

21655433134400 is a wasteful number, since it uses less digits than its factorization.

21655433134400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2761686 (or 2761658 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 41.

The spelling of 21655433134400 in words is "twenty-one trillion, six hundred fifty-five billion, four hundred thirty-three million, one hundred thirty-four thousand, four hundred".