21101212031 has 2 divisors, whose sum is σ = 21101212032. Its totient is φ = 21101212030.

The previous prime is 21101211997. The next prime is 21101212043. The reversal of 21101212031 is 13021210112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21101212031 is a prime.

It is a super-2 number, since 2×21101212031² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21101211997 and 21101212015.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101212061) 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 as a sum of consecutive naturals, namely, 10550606015 + 10550606016.

It is an arithmetic number, because the mean of its divisors is an integer number (10550606016).

Almost surely, 2^21101212031 is an apocalyptic number.

21101212031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101212031 is an equidigital number, since it uses as much as digits as its factorization.

21101212031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21101212031 its reverse (13021210112), we get a palindrome (34122422143).

The spelling of 21101212031 in words is "twenty-one billion, one hundred one million, two hundred twelve thousand, thirty-one".