21056513545650 has 192 divisors, whose sum is σ = 58005439307136. Its totient is φ = 5011899648000.

The previous prime is 21056513545607. The next prime is 21056513545651. The reversal of 21056513545650 is 5654531565012.

It is a self number, because there is not a number n which added to its sum of digits gives 21056513545650.

It is not an unprimeable number, because it can be changed into a prime (21056513545651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 55874254 + ... + 56249846.

It is an arithmetic number, because the mean of its divisors is an integer number (302111663058).

Almost surely, 2^{21056513545650} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21056513545650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29002719653568).

21056513545650 is an abundant number, since it is smaller than the sum of its proper divisors (36948925761486).

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

21056513545650 is a wasteful number, since it uses less digits than its factorization.

21056513545650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376237 (or 376232 counting only the distinct ones).

The product of its (nonzero) digits is 2700000, while the sum is 48.

The spelling of 21056513545650 in words is "twenty-one trillion, fifty-six billion, five hundred thirteen million, five hundred forty-five thousand, six hundred fifty".