1221021001011 has 24 divisors (see below), whose sum is σ = 1896990278400. Its totient is φ = 696561417552.

The previous prime is 1221021000919. The next prime is 1221021001033. The reversal of 1221021001011 is 1101001201221.

It is not a de Polignac number, because 1221021001011 - 2¹⁵ = 1221020968243 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221021001051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6845391 + ... + 7021496.

It is an arithmetic number, because the mean of its divisors is an integer number (79041261600).

Almost surely, 2^{1221021001011} is an apocalyptic number.

1221021001011 is a deficient number, since it is larger than the sum of its proper divisors (675969277389).

1221021001011 is a wasteful number, since it uses less digits than its factorization.

1221021001011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13867503 (or 13867496 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 1221021001011 its reverse (1101001201221), we get a palindrome (2322022202232).

The spelling of 1221021001011 in words is "one trillion, two hundred twenty-one billion, twenty-one million, one thousand, eleven".