1211217811 has 8 divisors (see below), whose sum is σ = 1214825040. Its totient is φ = 1207617408.

The previous prime is 1211217797. The next prime is 1211217817. The reversal of 1211217811 is 1187121121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1211217811 - 2⁹ = 1211217299 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211217817) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 692440 + ... + 694186.

It is an arithmetic number, because the mean of its divisors is an integer number (151853130).

Almost surely, 2^1211217811 is an apocalyptic number.

1211217811 is a deficient number, since it is larger than the sum of its proper divisors (3607229).

1211217811 is an equidigital number, since it uses as much as digits as its factorization.

1211217811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3413.

The product of its digits is 224, while the sum is 25.

The square root of 1211217811 is about 34802.5546619785. The cubic root of 1211217811 is about 1065.9596105983.

Adding to 1211217811 its reverse (1187121121), we get a palindrome (2398338932).

The spelling of 1211217811 in words is "one billion, two hundred eleven million, two hundred seventeen thousand, eight hundred eleven".