21320111345 has 12 divisors (see below), whose sum is σ = 27703530396. Its totient is φ = 15744081600.

The previous prime is 21320111291. The next prime is 21320111363. The reversal of 21320111345 is 54311102312.

It can be written as a sum of positive squares in 6 ways, for example, as 558471424 + 20761639921 = 23632^2 + 144089^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21320111345 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 21320111345.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 12614606 + ... + 12616295.

It is an arithmetic number, because the mean of its divisors is an integer number (2308627533).

Almost surely, 2^21320111345 is an apocalyptic number.

It is an amenable number.

21320111345 is a deficient number, since it is larger than the sum of its proper divisors (6383419051).

21320111345 is a wasteful number, since it uses less digits than its factorization.

21320111345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25230932 (or 25230919 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

Adding to 21320111345 its reverse (54311102312), we get a palindrome (75631213657).

The spelling of 21320111345 in words is "twenty-one billion, three hundred twenty million, one hundred eleven thousand, three hundred forty-five".