1231221210111 has 48 divisors (see below), whose sum is σ = 1819790943360. Its totient is φ = 801951321600.

The previous prime is 1231221210083. The next prime is 1231221210169. The reversal of 1231221210111 is 1110121221321.

It is a happy number.

1231221210111 is a `hidden beast` number, since 1 + 231 + 221 + 210 + 1 + 1 + 1 = 666.

It is not a de Polignac number, because 1231221210111 - 2⁶ = 1231221210047 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231221210181) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 170691141 + ... + 170698353.

It is an arithmetic number, because the mean of its divisors is an integer number (37912311320).

Almost surely, 2^{1231221210111} is an apocalyptic number.

1231221210111 is a deficient number, since it is larger than the sum of its proper divisors (588569733249).

1231221210111 is a wasteful number, since it uses less digits than its factorization.

1231221210111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9776 (or 9773 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 18.

Adding to 1231221210111 its reverse (1110121221321), we get a palindrome (2341342431432).

It can be divided in two parts, 1231221210 and 111, that added together give a palindrome (1231221321).

The spelling of 1231221210111 in words is "one trillion, two hundred thirty-one billion, two hundred twenty-one million, two hundred ten thousand, one hundred eleven".