1001002011221 has 2 divisors, whose sum is σ = 1001002011222. Its totient is φ = 1001002011220.

The previous prime is 1001002011209. The next prime is 1001002011223. The reversal of 1001002011221 is 1221102001001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 877755376996 + 123246634225 = 936886^2 + 351065^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1001002011221 is a prime.

Together with 1001002011223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001002011223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500501005610 + 500501005611.

It is an arithmetic number, because the mean of its divisors is an integer number (500501005611).

Almost surely, 2^{1001002011221} is an apocalyptic number.

It is an amenable number.

1001002011221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001002011221 is an equidigital number, since it uses as much as digits as its factorization.

1001002011221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 1001002011221 its reverse (1221102001001), we get a palindrome (2222104012222).

The spelling of 1001002011221 in words is "one trillion, one billion, two million, eleven thousand, two hundred twenty-one".