21144550542540 has 192 divisors, whose sum is σ = 61060643804160. Its totient is φ = 5463787069440.

The previous prime is 21144550542517. The next prime is 21144550542571. The reversal of 21144550542540 is 4524505544112.

It is a junction number, because it is equal to n+sod(n) for n = 21144550542492 and 21144550542501.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 217983771 + ... + 218080749.

It is an arithmetic number, because the mean of its divisors is an integer number (318024186480).

Almost surely, 2^{21144550542540} is an apocalyptic number.

21144550542540 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 21144550542540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30530321902080).

21144550542540 is an abundant number, since it is smaller than the sum of its proper divisors (39916093261620).

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

21144550542540 is a wasteful number, since it uses less digits than its factorization.

21144550542540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97632 (or 97630 counting only the distinct ones).

The product of its (nonzero) digits is 640000, while the sum is 42.

The spelling of 21144550542540 in words is "twenty-one trillion, one hundred forty-four billion, five hundred fifty million, five hundred forty-two thousand, five hundred forty".