21443131313 has 4 divisors (see below), whose sum is σ = 21504573300. Its totient is φ = 21381689328.

The previous prime is 21443131301. The next prime is 21443131327. The reversal of 21443131313 is 31313134412.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7511342224 + 13931789089 = 86668^2 + 118033^2 .

It is a cyclic number.

It is not a de Polignac number, because 21443131313 - 2⁶ = 21443131249 is a prime.

It is a super-2 number, since 2×21443131313² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21443131363) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30720470 + ... + 30721167.

It is an arithmetic number, because the mean of its divisors is an integer number (5376143325).

Almost surely, 2^21443131313 is an apocalyptic number.

It is an amenable number.

21443131313 is a deficient number, since it is larger than the sum of its proper divisors (61441987).

21443131313 is an equidigital number, since it uses as much as digits as its factorization.

21443131313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61441986.

The product of its digits is 2592, while the sum is 26.

Adding to 21443131313 its reverse (31313134412), we get a palindrome (52756265725).

The spelling of 21443131313 in words is "twenty-one billion, four hundred forty-three million, one hundred thirty-one thousand, three hundred thirteen".