21543243155680 has 48 divisors (see below), whose sum is σ = 50896189950480. Its totient is φ = 8617250194432.

The previous prime is 21543243155663. The next prime is 21543243155711. The reversal of 21543243155680 is 8655134234512.

It is a super-2 number, since 2×21543243155680² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54814911 + ... + 55206529.

It is an arithmetic number, because the mean of its divisors is an integer number (1060337290635).

Almost surely, 2^{21543243155680} is an apocalyptic number.

21543243155680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21543243155680 is an abundant number, since it is smaller than the sum of its proper divisors (29352946794800).

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

21543243155680 is a wasteful number, since it uses less digits than its factorization.

21543243155680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 735451 (or 735443 counting only the distinct ones).

The product of its (nonzero) digits is 3456000, while the sum is 49.

The spelling of 21543243155680 in words is "twenty-one trillion, five hundred forty-three billion, two hundred forty-three million, one hundred fifty-five thousand, six hundred eighty".