11881218001 has 3 divisors (see below), whose sum is σ = 11881327003. Its totient is φ = 11881109000.

The previous prime is 11881217981. The next prime is 11881218023. The reversal of 11881218001 is 10081218811.

The square root of 11881218001 is 109001.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 10081218811 = 1151 ⋅8758661.

It can be written as a sum of positive squares in only one way, i.e., 4872179601 + 7009038400 = 69801^2 + 83720^2 .

It is not a de Polignac number, because 11881218001 - 2¹¹ = 11881215953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11881218101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 54501 + ... + 163501.

Almost surely, 2^11881218001 is an apocalyptic number.

11881218001 is the 109001-st square number.

11881218001 is the 54501-st centered octagonal number.

It is an amenable number.

11881218001 is a deficient number, since it is larger than the sum of its proper divisors (109002).

11881218001 is an frugal number, since it uses more digits than its factorization.

11881218001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218002 (or 109001 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 31.

Multiplying 11881218001 by its product of nonzero digits (1024), we get a square (12166367233024 = 3488032²).

The spelling of 11881218001 in words is "eleven billion, eight hundred eighty-one million, two hundred eighteen thousand, one".