21131431311 has 4 divisors (see below), whose sum is σ = 28175241752. Its totient is φ = 14087620872.

The previous prime is 21131431297. The next prime is 21131431313. The reversal of 21131431311 is 11313413112.

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

It is not a de Polignac number, because 21131431311 - 2⁷ = 21131431183 is a prime.

It is a super-2 number, since 2×21131431311² (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 (21131431313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3521905216 + ... + 3521905221.

It is an arithmetic number, because the mean of its divisors is an integer number (7043810438).

Almost surely, 2^21131431311 is an apocalyptic number.

21131431311 is a deficient number, since it is larger than the sum of its proper divisors (7043810441).

21131431311 is an equidigital number, since it uses as much as digits as its factorization.

21131431311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7043810440.

The product of its digits is 216, while the sum is 21.

Adding to 21131431311 its reverse (11313413112), we get a palindrome (32444844423).

The spelling of 21131431311 in words is "twenty-one billion, one hundred thirty-one million, four hundred thirty-one thousand, three hundred eleven".