1221111271001 has 2 divisors, whose sum is σ = 1221111271002. Its totient is φ = 1221111271000.

The previous prime is 1221111270979. The next prime is 1221111271021. The reversal of 1221111271001 is 1001721111221.

It is a happy number.

It is an a-pointer prime, because the next prime (1221111271021) can be obtained adding 1221111271001 to its sum of digits (20).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 854559731776 + 366551539225 = 924424^2 + 605435^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221111271001 - 2¹⁰ = 1221111269977 is a prime.

It is a super-2 number, since 2×1221111271001² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1221111271021) 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, 610555635500 + 610555635501.

It is an arithmetic number, because the mean of its divisors is an integer number (610555635501).

Almost surely, 2^{1221111271001} is an apocalyptic number.

It is an amenable number.

1221111271001 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221111271001 is an equidigital number, since it uses as much as digits as its factorization.

1221111271001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56, while the sum is 20.

Adding to 1221111271001 its reverse (1001721111221), we get a palindrome (2222832382222).

The spelling of 1221111271001 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, two hundred seventy-one thousand, one".