1221021002021 has 2 divisors, whose sum is σ = 1221021002022. Its totient is φ = 1221021002020.

The previous prime is 1221021002017. The next prime is 1221021002063. The reversal of 1221021002021 is 1202001201221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 810090002500 + 410930999521 = 900050^2 + 641039^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221021002021 - 2² = 1221021002017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221021001987 and 1221021002005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221021002821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610510501010 + 610510501011.

It is an arithmetic number, because the mean of its divisors is an integer number (610510501011).

Almost surely, 2^{1221021002021} is an apocalyptic number.

It is an amenable number.

1221021002021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221021002021 is an equidigital number, since it uses as much as digits as its factorization.

1221021002021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 1221021002021 its reverse (1202001201221), we get a palindrome (2423022203242).

The spelling of 1221021002021 in words is "one trillion, two hundred twenty-one billion, twenty-one million, two thousand, twenty-one".