1211166121 has 16 divisors (see below), whose sum is σ = 1375277760. Its totient is φ = 1056525120.

The previous prime is 1211166109. The next prime is 1211166127. The reversal of 1211166121 is 1216611121.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1211166121 - 2¹³ = 1211157929 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211166092 and 1211166101.

It is not an unprimeable number, because it can be changed into a prime (1211166127) 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, 40351 + ... + 63643.

It is an arithmetic number, because the mean of its divisors is an integer number (85954860).

Almost surely, 2^1211166121 is an apocalyptic number.

1211166121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1211166121 is a deficient number, since it is larger than the sum of its proper divisors (164111639).

1211166121 is a wasteful number, since it uses less digits than its factorization.

1211166121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23496.

The product of its digits is 144, while the sum is 22.

The square root of 1211166121 is about 34801.8120361570. The cubic root of 1211166121 is about 1065.9444467317.

Multiplying 1211166121 by its sum of digits (22), we get a palindrome (26645654662).

Adding to 1211166121 its reverse (1216611121), we get a palindrome (2427777242).

The spelling of 1211166121 in words is "one billion, two hundred eleven million, one hundred sixty-six thousand, one hundred twenty-one".