1211994018 has 12 divisors (see below), whose sum is σ = 2625987078. Its totient is φ = 403998000.

The previous prime is 1211993969. The next prime is 1211994019. The reversal of 1211994018 is 8104991121.

It can be written as a sum of positive squares in only one way, i.e., 1209161529 + 2832489 = 34773^2 + 1683^2 .

It is not an unprimeable number, because it can be changed into a prime (1211994019) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 33666483 + ... + 33666518.

Almost surely, 2^1211994018 is an apocalyptic number.

1211994018 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1211994018 is an abundant number, since it is smaller than the sum of its proper divisors (1413993060).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211994018 is a wasteful number, since it uses less digits than its factorization.

1211994018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67333009 (or 67333006 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 1211994018 is about 34813.7044567222. The cubic root of 1211994018 is about 1066.1872681453.

The spelling of 1211994018 in words is "one billion, two hundred eleven million, nine hundred ninety-four thousand, eighteen".