1231121001001 has 2 divisors, whose sum is σ = 1231121001002. Its totient is φ = 1231121001000.

The previous prime is 1231121000999. The next prime is 1231121001017. The reversal of 1231121001001 is 1001001211321.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1017473672601 + 213647328400 = 1008699^2 + 462220^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231121001001 - 2¹ = 1231121000999 is a prime.

Together with 1231121000999, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1231121401001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615560500500 + 615560500501.

It is an arithmetic number, because the mean of its divisors is an integer number (615560500501).

Almost surely, 2^{1231121001001} is an apocalyptic number.

It is an amenable number.

1231121001001 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231121001001 is an equidigital number, since it uses as much as digits as its factorization.

1231121001001 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 1231121001001 its reverse (1001001211321), we get a palindrome (2232122212322).

The spelling of 1231121001001 in words is "one trillion, two hundred thirty-one billion, one hundred twenty-one million, one thousand, one".