21542644081200 has 240 divisors, whose sum is σ = 75295471709952. Its totient is φ = 5221507200000.

The previous prime is 21542644081181. The next prime is 21542644081207. The reversal of 21542644081200 is 218044624512.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×21542644081200² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21542644081207) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 73655250 + ... + 73947150.

Almost surely, 2^{21542644081200} is an apocalyptic number.

21542644081200 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 21542644081200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37647735854976).

21542644081200 is an abundant number, since it is smaller than the sum of its proper divisors (53752827628752).

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

21542644081200 is a wasteful number, since it uses less digits than its factorization.

21542644081200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297524 (or 297513 counting only the distinct ones).

The product of its (nonzero) digits is 122880, while the sum is 39.

The spelling of 21542644081200 in words is "twenty-one trillion, five hundred forty-two billion, six hundred forty-four million, eighty-one thousand, two hundred".