21001001011231 has 2 divisors, whose sum is σ = 21001001011232. Its totient is φ = 21001001011230.

The previous prime is 21001001011189. The next prime is 21001001011253. The reversal of 21001001011231 is 13211010010012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21001001011231 - 2¹³ = 21001001003039 is a prime.

It is a super-2 number, since 2×21001001011231² (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 (21001001011531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500500505615 + 10500500505616.

It is an arithmetic number, because the mean of its divisors is an integer number (10500500505616).

Almost surely, 2^{21001001011231} is an apocalyptic number.

21001001011231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001001011231 is an equidigital number, since it uses as much as digits as its factorization.

21001001011231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 21001001011231 its reverse (13211010010012), we get a palindrome (34212011021243).

The spelling of 21001001011231 in words is "twenty-one trillion, one billion, one million, eleven thousand, two hundred thirty-one".