21403312131 has 4 divisors (see below), whose sum is σ = 28537749512. Its totient is φ = 14268874752.

The previous prime is 21403312127. The next prime is 21403312181. The reversal of 21403312131 is 13121330412.

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

It is not a de Polignac number, because 21403312131 - 2² = 21403312127 is a prime.

It is a super-2 number, since 2×21403312131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21403312098 and 21403312107.

It is not an unprimeable number, because it can be changed into a prime (21403312121) 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, 3567218686 + ... + 3567218691.

It is an arithmetic number, because the mean of its divisors is an integer number (7134437378).

Almost surely, 2^21403312131 is an apocalyptic number.

21403312131 is a deficient number, since it is larger than the sum of its proper divisors (7134437381).

21403312131 is an equidigital number, since it uses as much as digits as its factorization.

21403312131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7134437380.

The product of its (nonzero) digits is 432, while the sum is 21.

Adding to 21403312131 its reverse (13121330412), we get a palindrome (34524642543).

The spelling of 21403312131 in words is "twenty-one billion, four hundred three million, three hundred twelve thousand, one hundred thirty-one".