21500442421111 has 4 divisors (see below), whose sum is σ = 21500707550400. Its totient is φ = 21500177291824.

The previous prime is 21500442421103. The next prime is 21500442421201. The reversal of 21500442421111 is 11112424400512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21500442421111 - 2³ = 21500442421103 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21500442421111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500442421811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132442966 + ... + 132605203.

It is an arithmetic number, because the mean of its divisors is an integer number (5375176887600).

Almost surely, 2^{21500442421111} is an apocalyptic number.

21500442421111 is a deficient number, since it is larger than the sum of its proper divisors (265129289).

21500442421111 is an equidigital number, since it uses as much as digits as its factorization.

21500442421111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265129288.

The product of its (nonzero) digits is 2560, while the sum is 28.

Adding to 21500442421111 its reverse (11112424400512), we get a palindrome (32612866821623).

The spelling of 21500442421111 in words is "twenty-one trillion, five hundred billion, four hundred forty-two million, four hundred twenty-one thousand, one hundred eleven".