1221021020011 has 16 divisors (see below), whose sum is σ = 1392355893600. Its totient is φ = 1060750499328.

The previous prime is 1221021019997. The next prime is 1221021020017. The reversal of 1221021020011 is 1100201201221.

It is not a de Polignac number, because 1221021020011 - 2⁵ = 1221021019979 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221021019973 and 1221021020000.

It is not an unprimeable number, because it can be changed into a prime (1221021020017) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5599005 + ... + 5812993.

It is an arithmetic number, because the mean of its divisors is an integer number (87022243350).

Almost surely, 2^{1221021020011} is an apocalyptic number.

1221021020011 is a deficient number, since it is larger than the sum of its proper divisors (171334873589).

1221021020011 is a wasteful number, since it uses less digits than its factorization.

1221021020011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239838.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1221021020011 its reverse (1100201201221), we get a palindrome (2321222221232).

The spelling of 1221021020011 in words is "one trillion, two hundred twenty-one billion, twenty-one million, twenty thousand, eleven".