1221221221001 has 8 divisors (see below), whose sum is σ = 1239508806240. Its totient is φ = 1202935412448.

The previous prime is 1221221220997. The next prime is 1221221221009. The reversal of 1221221221001 is 1001221221221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221221221001 - 2² = 1221221220997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1221221221009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 974510 + ... + 1841768.

It is an arithmetic number, because the mean of its divisors is an integer number (154938600780).

Almost surely, 2^{1221221221001} is an apocalyptic number.

It is an amenable number.

1221221221001 is a deficient number, since it is larger than the sum of its proper divisors (18287585239).

1221221221001 is an equidigital number, since it uses as much as digits as its factorization.

1221221221001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 888343.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1221221221001 its reverse (1001221221221), we get a palindrome (2222442442222).

The spelling of 1221221221001 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred twenty-one thousand, one".