21621210550456 has 64 divisors (see below), whose sum is σ = 46577264112000. Its totient is φ = 9305685452160.

The previous prime is 21621210550453. The next prime is 21621210550483. The reversal of 21621210550456 is 65405501212612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621210550453) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 201991 + ... + 6578998.

It is an arithmetic number, because the mean of its divisors is an integer number (727769751750).

Almost surely, 2^{21621210550456} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21621210550456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23288632056000).

21621210550456 is an abundant number, since it is smaller than the sum of its proper divisors (24956053561544).

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

21621210550456 is a wasteful number, since it uses less digits than its factorization.

21621210550456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6782932 (or 6782928 counting only the distinct ones).

The product of its (nonzero) digits is 144000, while the sum is 40.

The spelling of 21621210550456 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred ten million, five hundred fifty thousand, four hundred fifty-six".