1211101221 has 24 divisors (see below), whose sum is σ = 1791592992. Its totient is φ = 727117600.

The previous prime is 1211101187. The next prime is 1211101237. The reversal of 1211101221 is 1221011121.

It is not a de Polignac number, because 1211101221 - 2⁷ = 1211101093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1211101197 and 1211101206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211101261) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23251 + ... + 54431.

It is an arithmetic number, because the mean of its divisors is an integer number (74649708).

Almost surely, 2^1211101221 is an apocalyptic number.

1211101221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1211101221 is a deficient number, since it is larger than the sum of its proper divisors (580491771).

1211101221 is a wasteful number, since it uses less digits than its factorization.

1211101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31313 (or 31302 counting only the distinct ones).

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

The square root of 1211101221 is about 34800.8796009526. The cubic root of 1211101221 is about 1065.9254069459.

Adding to 1211101221 its reverse (1221011121), we get a palindrome (2432112342).

The spelling of 1211101221 in words is "one billion, two hundred eleven million, one hundred one thousand, two hundred twenty-one".