21310111013 has 6 divisors (see below), whose sum is σ = 21452195142. Its totient is φ = 21168961800.

The previous prime is 21310111001. The next prime is 21310111033. The reversal of 21310111013 is 31011101312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20018571169 + 1291539844 = 141487^2 + 35938^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21310111013 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 (21310111033) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 444506 + ... + 490107.

It is an arithmetic number, because the mean of its divisors is an integer number (3575365857).

Almost surely, 2^21310111013 is an apocalyptic number.

It is an amenable number.

21310111013 is a deficient number, since it is larger than the sum of its proper divisors (142084129).

21310111013 is an frugal number, since it uses more digits than its factorization.

21310111013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 934915 (or 934764 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 14.

Adding to 21310111013 its reverse (31011101312), we get a palindrome (52321212325).

The spelling of 21310111013 in words is "twenty-one billion, three hundred ten million, one hundred eleven thousand, thirteen".