21515445224550 has 144 divisors (see below), whose sum is σ = 59952812774400. Its totient is φ = 5736775998240.

The previous prime is 21515445224477. The next prime is 21515445224561. The reversal of 21515445224550 is 5542254451512.

21515445224550 is a `hidden beast` number, since 2 + 1 + 5 + 1 + 5 + 44 + 52 + 2 + 4 + 550 = 666.

It is a super-2 number, since 2×21515445224550² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a junction number, because it is equal to n+sod(n) for n = 21515445224496 and 21515445224505.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 107585551 + ... + 107785349.

It is an arithmetic number, because the mean of its divisors is an integer number (416338977600).

Almost surely, 2^{21515445224550} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21515445224550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29976406387200).

21515445224550 is an abundant number, since it is smaller than the sum of its proper divisors (38437367549850).

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

21515445224550 is a wasteful number, since it uses less digits than its factorization.

21515445224550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208689 (or 208672 counting only the distinct ones).

The product of its (nonzero) digits is 1600000, while the sum is 45.

The spelling of 21515445224550 in words is "twenty-one trillion, five hundred fifteen billion, four hundred forty-five million, two hundred twenty-four thousand, five hundred fifty".