1231221021001 has 4 divisors (see below), whose sum is σ = 1231275232404. Its totient is φ = 1231166809600.

The previous prime is 1231221020977. The next prime is 1231221021013. The reversal of 1231221021001 is 1001201221321.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 844864297225 + 386356723776 = 919165^2 + 621576^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231221021001 - 2⁷ = 1231221020873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1231221021071) 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 in 3 ways as a sum of consecutive naturals, for example, 27071620 + ... + 27117061.

It is an arithmetic number, because the mean of its divisors is an integer number (307818808101).

Almost surely, 2^{1231221021001} is an apocalyptic number.

It is an amenable number.

1231221021001 is a deficient number, since it is larger than the sum of its proper divisors (54211403).

1231221021001 is an equidigital number, since it uses as much as digits as its factorization.

1231221021001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54211402.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 1231221021001 its reverse (1001201221321), we get a palindrome (2232422242322).

The spelling of 1231221021001 in words is "one trillion, two hundred thirty-one billion, two hundred twenty-one million, twenty-one thousand, one".