1211123505 has 16 divisors (see below), whose sum is σ = 1938239424. Its totient is φ = 645785280.

The previous prime is 1211123497. The next prime is 1211123513. The reversal of 1211123505 is 5053211121.

It is an interprime number because it is at equal distance from previous prime (1211123497) and next prime (1211123513).

It is not a de Polignac number, because 1211123505 - 2³ = 1211123497 is a prime.

It is a super-3 number, since 3×1211123505³ (a number of 28 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 102567 + ... + 113763.

It is an arithmetic number, because the mean of its divisors is an integer number (121139964).

Almost surely, 2^1211123505 is an apocalyptic number.

1211123505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1211123505 is a deficient number, since it is larger than the sum of its proper divisors (727115919).

1211123505 is a wasteful number, since it uses less digits than its factorization.

1211123505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18416.

The product of its (nonzero) digits is 300, while the sum is 21.

The square root of 1211123505 is about 34801.1997638012. The cubic root of 1211123505 is about 1065.9319445047.

Adding to 1211123505 its reverse (5053211121), we get a palindrome (6264334626).

The spelling of 1211123505 in words is "one billion, two hundred eleven million, one hundred twenty-three thousand, five hundred five".