1221020202001 has 4 divisors (see below), whose sum is σ = 1237746506212. Its totient is φ = 1204293897792.

The previous prime is 1221020201837. The next prime is 1221020202011. The reversal of 1221020202001 is 1002020201221.

It is a happy number.

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 920738121601 + 300282080400 = 959551^2 + 547980^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221020202001 - 2¹⁵ = 1221020169233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221020202011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8363151996 + ... + 8363152141.

It is an arithmetic number, because the mean of its divisors is an integer number (309436626553).

Almost surely, 2^{1221020202001} is an apocalyptic number.

It is an amenable number.

1221020202001 is a deficient number, since it is larger than the sum of its proper divisors (16726304211).

1221020202001 is an equidigital number, since it uses as much as digits as its factorization.

1221020202001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16726304210.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 1221020202001 its reverse (1002020201221), we get a palindrome (2223040403222).

The spelling of 1221020202001 in words is "one trillion, two hundred twenty-one billion, twenty million, two hundred two thousand, one".