21001220111012 has 12 divisors (see below), whose sum is σ = 38019450201180. Its totient is φ = 10138520053536.

The previous prime is 21001220110993. The next prime is 21001220111093. The reversal of 21001220111012 is 21011102210012.

It can be written as a sum of positive squares in 2 ways, for example, as 16484379529216 + 4516840581796 = 4060096^2 + 2125286^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90522500363 + ... + 90522500594.

It is an arithmetic number, because the mean of its divisors is an integer number (3168287516765).

Almost surely, 2^{21001220111012} is an apocalyptic number.

It is an amenable number.

21001220111012 is a deficient number, since it is larger than the sum of its proper divisors (17018230090168).

21001220111012 is a wasteful number, since it uses less digits than its factorization.

21001220111012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181045000990 (or 181045000988 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21001220111012 its reverse (21011102210012), we get a palindrome (42012322321024).

The spelling of 21001220111012 in words is "twenty-one trillion, one billion, two hundred twenty million, one hundred eleven thousand, twelve".