1001001221221 has 4 divisors (see below), whose sum is σ = 1044523013472. Its totient is φ = 957479428972.

The previous prime is 1001001221189. The next prime is 1001001221273. The reversal of 1001001221221 is 1221221001001.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1001001221221 - 2⁵ = 1001001221189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001001227221) 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, 21760896091 + ... + 21760896136.

It is an arithmetic number, because the mean of its divisors is an integer number (261130753368).

Almost surely, 2^{1001001221221} is an apocalyptic number.

It is an amenable number.

1001001221221 is a deficient number, since it is larger than the sum of its proper divisors (43521792251).

1001001221221 is an equidigital number, since it uses as much as digits as its factorization.

1001001221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43521792250.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1001001221221 its reverse (1221221001001), we get a palindrome (2222222222222).

The spelling of 1001001221221 in words is "one trillion, one billion, one million, two hundred twenty-one thousand, two hundred twenty-one".