21320444111 has 4 divisors (see below), whose sum is σ = 21330404424. Its totient is φ = 21310483800.

The previous prime is 21320444077. The next prime is 21320444191. The reversal of 21320444111 is 11144402312.

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 21320444111 - 2²² = 21316249807 is a prime.

It is a super-2 number, since 2×21320444111² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21320444191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4976945 + ... + 4981226.

It is an arithmetic number, because the mean of its divisors is an integer number (5332601106).

Almost surely, 2^21320444111 is an apocalyptic number.

21320444111 is a deficient number, since it is larger than the sum of its proper divisors (9960313).

21320444111 is an equidigital number, since it uses as much as digits as its factorization.

21320444111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9960312.

The product of its (nonzero) digits is 768, while the sum is 23.

Adding to 21320444111 its reverse (11144402312), we get a palindrome (32464846423).

The spelling of 21320444111 in words is "twenty-one billion, three hundred twenty million, four hundred forty-four thousand, one hundred eleven".