21021550543 has 16 divisors (see below), whose sum is σ = 25420145920. Its totient is φ = 16981664256.

The previous prime is 21021550531. The next prime is 21021550547. The reversal of 21021550543 is 34505512012.

It is a cyclic number.

It is not a de Polignac number, because 21021550543 - 2⁹ = 21021550031 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021550547) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 383805 + ... + 435142.

It is an arithmetic number, because the mean of its divisors is an integer number (1588759120).

Almost surely, 2^21021550543 is an apocalyptic number.

21021550543 is a deficient number, since it is larger than the sum of its proper divisors (4398595377).

21021550543 is a wasteful number, since it uses less digits than its factorization.

21021550543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 819166.

The product of its (nonzero) digits is 6000, while the sum is 28.

The spelling of 21021550543 in words is "twenty-one billion, twenty-one million, five hundred fifty thousand, five hundred forty-three".