1211218138 has 16 divisors (see below), whose sum is σ = 1959863976. Its totient is φ = 558086400.

The previous prime is 1211218079. The next prime is 1211218171. The reversal of 1211218138 is 8318121121.

It can be written as a sum of positive squares in 4 ways, for example, as 1196952409 + 14265729 = 34597^2 + 3777^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23131 + ... + 54382.

Almost surely, 2^1211218138 is an apocalyptic number.

1211218138 is a deficient number, since it is larger than the sum of its proper divisors (748645838).

1211218138 is a wasteful number, since it uses less digits than its factorization.

1211218138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78129.

The product of its digits is 768, while the sum is 28.

The square root of 1211218138 is about 34802.5593599092. The cubic root of 1211218138 is about 1065.9597065262.

Adding to 1211218138 its reverse (8318121121), we get a palindrome (9529339259).

The spelling of 1211218138 in words is "one billion, two hundred eleven million, two hundred eighteen thousand, one hundred thirty-eight".