21542320800 has 1728 divisors, whose sum is σ = 105780729600. Its totient is φ = 4064256000.

The previous prime is 21542320769. The next prime is 21542320801. The reversal of 21542320800 is 802324512.

21542320800 is a `hidden beast` number, since 21 + 542 + 3 + 20 + 80 + 0 = 666.

It is a super-2 number, since 2×21542320800² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21542320801) by changing a digit.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 353152770 + ... + 353152830.

It is an arithmetic number, because the mean of its divisors is an integer number (61215700).

Almost surely, 2^21542320800 is an apocalyptic number.

21542320800 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 21542320800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52890364800).

21542320800 is an abundant number, since it is smaller than the sum of its proper divisors (84238408800).

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

21542320800 is a wasteful number, since it uses less digits than its factorization.

21542320800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132 (or 102 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The spelling of 21542320800 in words is "twenty-one billion, five hundred forty-two million, three hundred twenty thousand, eight hundred".