21311135613 has 16 divisors (see below), whose sum is σ = 31897541760. Its totient is φ = 14060953728.

The previous prime is 21311135609. The next prime is 21311135627. The reversal of 21311135613 is 31653111312.

It is a happy number.

21311135613 is a `hidden beast` number, since 2 + 1 + 3 + 1 + 11 + 35 + 613 = 666.

It is not a de Polignac number, because 21311135613 - 2² = 21311135609 is a prime.

It is a super-2 number, since 2×21311135613² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311135633) 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 15 ways as a sum of consecutive naturals, for example, 4065945 + ... + 4071182.

It is an arithmetic number, because the mean of its divisors is an integer number (1993596360).

Almost surely, 2^21311135613 is an apocalyptic number.

It is an amenable number.

21311135613 is a deficient number, since it is larger than the sum of its proper divisors (10586406147).

21311135613 is an equidigital number, since it uses as much as digits as its factorization.

21311135613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8137233 (or 8137227 counting only the distinct ones).

The product of its digits is 1620, while the sum is 27.

Adding to 21311135613 its reverse (31653111312), we get a palindrome (52964246925).

The spelling of 21311135613 in words is "twenty-one billion, three hundred eleven million, one hundred thirty-five thousand, six hundred thirteen".