21005143361280 has 3456 divisors, whose sum is σ = 90167478912000. Its totient is φ = 4608448266240.

The previous prime is 21005143361263. The next prime is 21005143361281. The reversal of 21005143361280 is 8216334150012.

21005143361280 is a `hidden beast` number, since 2 + 1 + 0 + 0 + 5 + 1 + 4 + 33 + 612 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (3456).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21005143361281) by changing a digit.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 196309750987 + ... + 196309751093.

It is an arithmetic number, because the mean of its divisors is an integer number (26090127000).

Almost surely, 2^{21005143361280} is an apocalyptic number.

21005143361280 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 21005143361280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45083739456000).

21005143361280 is an abundant number, since it is smaller than the sum of its proper divisors (69162335550720).

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

21005143361280 is a wasteful number, since it uses less digits than its factorization.

21005143361280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272 (or 239 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 21005143361280 in words is "twenty-one trillion, five billion, one hundred forty-three million, three hundred sixty-one thousand, two hundred eighty".