21191900543 has 8 divisors (see below), whose sum is σ = 23682301776. Its totient is φ = 18795476800.

The previous prime is 21191900537. The next prime is 21191900551. The reversal of 21191900543 is 34500919112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21191900543 - 2¹² = 21191896447 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 (21191900533) 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 7 ways as a sum of consecutive naturals, for example, 23493896 + ... + 23494797.

It is an arithmetic number, because the mean of its divisors is an integer number (2960287722).

Almost surely, 2^21191900543 is an apocalyptic number.

21191900543 is a deficient number, since it is larger than the sum of its proper divisors (2490401233).

21191900543 is a wasteful number, since it uses less digits than its factorization.

21191900543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46988745.

The product of its (nonzero) digits is 9720, while the sum is 35.

The spelling of 21191900543 in words is "twenty-one billion, one hundred ninety-one million, nine hundred thousand, five hundred forty-three".