21001212310031 has 2 divisors, whose sum is σ = 21001212310032. Its totient is φ = 21001212310030.

The previous prime is 21001212310009. The next prime is 21001212310081. The reversal of 21001212310031 is 13001321210012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21001212310031 - 2¹⁸ = 21001212047887 is a prime.

It is a super-2 number, since 2×21001212310031² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21001212309991 and 21001212310009.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001212310081) 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, 10500606155015 + 10500606155016.

It is an arithmetic number, because the mean of its divisors is an integer number (10500606155016).

Almost surely, 2^{21001212310031} is an apocalyptic number.

21001212310031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001212310031 is an equidigital number, since it uses as much as digits as its factorization.

21001212310031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21001212310031 its reverse (13001321210012), we get a palindrome (34002533520043).

The spelling of 21001212310031 in words is "twenty-one trillion, one billion, two hundred twelve million, three hundred ten thousand, thirty-one".