21518440843200 has 672 divisors, whose sum is σ = 81505409272320. Its totient is φ = 4868613734400.

The previous prime is 21518440843199. The next prime is 21518440843243. The reversal of 21518440843200 is 234804481512.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

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, 1800248424 + ... + 1800260376.

Almost surely, 2^{21518440843200} is an apocalyptic number.

21518440843200 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 21518440843200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40752704636160).

21518440843200 is an abundant number, since it is smaller than the sum of its proper divisors (59986968429120).

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

21518440843200 is a wasteful number, since it uses less digits than its factorization.

21518440843200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12525 (or 12510 counting only the distinct ones).

The product of its (nonzero) digits is 245760, while the sum is 42.

The spelling of 21518440843200 in words is "twenty-one trillion, five hundred eighteen billion, four hundred forty million, eight hundred forty-three thousand, two hundred".