21001012123031 has 2 divisors, whose sum is σ = 21001012123032. Its totient is φ = 21001012123030.

The previous prime is 21001012123027. The next prime is 21001012123057. The reversal of 21001012123031 is 13032121010012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21001012123031 - 2² = 21001012123027 is a prime.

It is a super-2 number, since 2×21001012123031² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001012123081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500506061515 + 10500506061516.

It is an arithmetic number, because the mean of its divisors is an integer number (10500506061516).

Almost surely, 2^{21001012123031} is an apocalyptic number.

21001012123031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001012123031 is an equidigital number, since it uses as much as digits as its factorization.

21001012123031 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 21001012123031 its reverse (13032121010012), we get a palindrome (34033133133043).

The spelling of 21001012123031 in words is "twenty-one trillion, one billion, twelve million, one hundred twenty-three thousand, thirty-one".