1211085611 has 4 divisors (see below), whose sum is σ = 1211404272. Its totient is φ = 1210766952.

The previous prime is 1211085607. The next prime is 1211085637. The reversal of 1211085611 is 1165801121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1165801121 = 89 ⋅13098889.

It is a cyclic number.

It is not a de Polignac number, because 1211085611 - 2² = 1211085607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211085011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 153560 + ... + 161253.

It is an arithmetic number, because the mean of its divisors is an integer number (302851068).

Almost surely, 2^1211085611 is an apocalyptic number.

1211085611 is a deficient number, since it is larger than the sum of its proper divisors (318661).

1211085611 is an equidigital number, since it uses as much as digits as its factorization.

1211085611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318660.

The product of its (nonzero) digits is 480, while the sum is 26.

The square root of 1211085611 is about 34800.6553242895. The cubic root of 1211085611 is about 1065.9208273213.

Adding to 1211085611 its reverse (1165801121), we get a palindrome (2376886732).

The spelling of 1211085611 in words is "one billion, two hundred eleven million, eighty-five thousand, six hundred eleven".