21210031331 has 2 divisors, whose sum is σ = 21210031332. Its totient is φ = 21210031330.

The previous prime is 21210031319. The next prime is 21210031333. The reversal of 21210031331 is 13313001212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21210031331 - 2¹⁰ = 21210030307 is a prime.

It is a super-2 number, since 2×21210031331² (a number of 21 digits) contains 22 as substring.

Together with 21210031333, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21210031333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605015665 + 10605015666.

It is an arithmetic number, because the mean of its divisors is an integer number (10605015666).

Almost surely, 2^21210031331 is an apocalyptic number.

21210031331 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210031331 is an equidigital number, since it uses as much as digits as its factorization.

21210031331 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 17.

Adding to 21210031331 its reverse (13313001212), we get a palindrome (34523032543).

The spelling of 21210031331 in words is "twenty-one billion, two hundred ten million, thirty-one thousand, three hundred thirty-one".