1211221105 has 16 divisors (see below), whose sum is σ = 1504788480. Its totient is φ = 934815168.

The previous prime is 1211221097. The next prime is 1211221111. The reversal of 1211221105 is 5011221121.

It is a cyclic number.

It is not a de Polignac number, because 1211221105 - 2³ = 1211221097 is a prime.

It is a super-4 number, since 4×1211221105⁴ (a number of 37 digits) contains 4444 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 238624 + ... + 243646.

It is an arithmetic number, because the mean of its divisors is an integer number (94049280).

Almost surely, 2^1211221105 is an apocalyptic number.

It is an amenable number.

1211221105 is a deficient number, since it is larger than the sum of its proper divisors (293567375).

1211221105 is a wasteful number, since it uses less digits than its factorization.

1211221105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6720.

The product of its (nonzero) digits is 40, while the sum is 16.

The square root of 1211221105 is about 34802.6019860585. The cubic root of 1211221105 is about 1065.9605769172.

Adding to 1211221105 its sum of digits (16), we get a palindrome (1211221121).

Adding to 1211221105 its reverse (5011221121), we get a palindrome (6222442226).

The spelling of 1211221105 in words is "one billion, two hundred eleven million, two hundred twenty-one thousand, one hundred five".