1202221121821 has 2 divisors, whose sum is σ = 1202221121822. Its totient is φ = 1202221121820.

The previous prime is 1202221121819. The next prime is 1202221121851. The reversal of 1202221121821 is 1281211222021.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 615903192025 + 586317929796 = 784795^2 + 765714^2 .

It is a cyclic number.

It is not a de Polignac number, because 1202221121821 - 2¹ = 1202221121819 is a prime.

Together with 1202221121819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1202221121851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 601110560910 + 601110560911.

It is an arithmetic number, because the mean of its divisors is an integer number (601110560911).

Almost surely, 2^{1202221121821} is an apocalyptic number.

It is an amenable number.

1202221121821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1202221121821 is an equidigital number, since it uses as much as digits as its factorization.

1202221121821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 512, while the sum is 25.

Adding to 1202221121821 its reverse (1281211222021), we get a palindrome (2483432343842).

The spelling of 1202221121821 in words is "one trillion, two hundred two billion, two hundred twenty-one million, one hundred twenty-one thousand, eight hundred twenty-one".