1211121221001 has 16 divisors (see below), whose sum is σ = 1658770953600. Its totient is φ = 785450677248.

The previous prime is 1211121220997. The next prime is 1211121221003. The reversal of 1211121221001 is 1001221211121.

It is a happy number.

It is not a de Polignac number, because 1211121221001 - 2² = 1211121220997 is a prime.

It is a super-2 number, since 2×1211121221001² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1211121221003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 361461 + ... + 1597778.

It is an arithmetic number, because the mean of its divisors is an integer number (103673184600).

Almost surely, 2^{1211121221001} is an apocalyptic number.

It is an amenable number.

1211121221001 is a deficient number, since it is larger than the sum of its proper divisors (447649732599).

1211121221001 is a wasteful number, since it uses less digits than its factorization.

1211121221001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1964848.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1211121221001 its reverse (1001221211121), we get a palindrome (2212342432122).

The spelling of 1211121221001 in words is "one trillion, two hundred eleven billion, one hundred twenty-one million, two hundred twenty-one thousand, one".