1211164721 has 8 divisors (see below), whose sum is σ = 1320842880. Its totient is φ = 1103845392.

The previous prime is 1211164693. The next prime is 1211164733. The reversal of 1211164721 is 1274611121.

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

It is not a de Polignac number, because 1211164721 - 2²² = 1206970417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1211164781) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 588635 + ... + 590688.

It is an arithmetic number, because the mean of its divisors is an integer number (165105360).

Almost surely, 2^1211164721 is an apocalyptic number.

It is an amenable number.

1211164721 is a deficient number, since it is larger than the sum of its proper divisors (109678159).

1211164721 is a wasteful number, since it uses less digits than its factorization.

1211164721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1179415.

The product of its digits is 672, while the sum is 26.

The square root of 1211164721 is about 34801.7919222560. The cubic root of 1211164721 is about 1065.9440360193.

Adding to 1211164721 its reverse (1274611121), we get a palindrome (2485775842).

The spelling of 1211164721 in words is "one billion, two hundred eleven million, one hundred sixty-four thousand, seven hundred twenty-one".