1211918564 has 12 divisors (see below), whose sum is σ = 2160874044. Its totient is φ = 594525984.

The previous prime is 1211918563. The next prime is 1211918567. The reversal of 1211918564 is 4658191121.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 693900964 + 518017600 = 26342^2 + 22760^2 .

It is not an unprimeable number, because it can be changed into a prime (1211918563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2858087 + ... + 2858510.

It is an arithmetic number, because the mean of its divisors is an integer number (180072837).

Almost surely, 2^1211918564 is an apocalyptic number.

It is an amenable number.

1211918564 is a deficient number, since it is larger than the sum of its proper divisors (948955480).

1211918564 is a wasteful number, since it uses less digits than its factorization.

1211918564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5716654 (or 5716652 counting only the distinct ones).

The product of its digits is 17280, while the sum is 38.

The square root of 1211918564 is about 34812.6207574207. The cubic root of 1211918564 is about 1066.1651421385.

The spelling of 1211918564 in words is "one billion, two hundred eleven million, nine hundred eighteen thousand, five hundred sixty-four".