1221221101011 has 32 divisors (see below), whose sum is σ = 1713630124800. Its totient is φ = 772772307840.

The previous prime is 1221221100977. The next prime is 1221221101039. The reversal of 1221221101011 is 1101011221221.

It is a happy number.

It is not a de Polignac number, because 1221221101011 - 2⁶ = 1221221100947 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221221101211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 146185 + ... + 1569653.

It is an arithmetic number, because the mean of its divisors is an integer number (53550941400).

Almost surely, 2^{1221221101011} is an apocalyptic number.

1221221101011 is a deficient number, since it is larger than the sum of its proper divisors (492409023789).

1221221101011 is a wasteful number, since it uses less digits than its factorization.

1221221101011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1423699.

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

Adding to 1221221101011 its reverse (1101011221221), we get a palindrome (2322232322232).

The spelling of 1221221101011 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, one hundred one thousand, eleven".