18206665949 has 4 divisors (see below), whose sum is σ = 18213086364. Its totient is φ = 18200245536.

The previous prime is 18206665891. The next prime is 18206665969. The reversal of 18206665949 is 94956660281.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6333294724 + 11873371225 = 79582^2 + 108965^2 .

It is a cyclic number.

It is not a de Polignac number, because 18206665949 - 2²⁴ = 18189888733 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18206665894 and 18206665903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18206665969) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3205952 + ... + 3211625.

It is an arithmetic number, because the mean of its divisors is an integer number (4553271591).

Almost surely, 2^18206665949 is an apocalyptic number.

It is an amenable number.

18206665949 is a deficient number, since it is larger than the sum of its proper divisors (6420415).

18206665949 is an equidigital number, since it uses as much as digits as its factorization.

18206665949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6420414.

The product of its (nonzero) digits is 5598720, while the sum is 56.

The spelling of 18206665949 in words is "eighteen billion, two hundred six million, six hundred sixty-five thousand, nine hundred forty-nine".