1221011001001 has 8 divisors (see below), whose sum is σ = 1344232296000. Its totient is φ = 1099826421840.

The previous prime is 1221011000987. The next prime is 1221011001011. The reversal of 1221011001001 is 1001001101221.

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 1221011001001 - 2⁵ = 1221011000969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221011001011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 509177701 + ... + 509180098.

It is an arithmetic number, because the mean of its divisors is an integer number (168029037000).

Almost surely, 2^{1221011001001} is an apocalyptic number.

1221011001001 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221011001001 is a deficient number, since it is larger than the sum of its proper divisors (123221294999).

1221011001001 is a wasteful number, since it uses less digits than its factorization.

1221011001001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1018357919.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 1221011001001 its reverse (1001001101221), we get a palindrome (2222012102222).

The spelling of 1221011001001 in words is "one trillion, two hundred twenty-one billion, eleven million, one thousand, one".