18218367649 has 4 divisors (see below), whose sum is σ = 18806056960. Its totient is φ = 17630678340.

The previous prime is 18218367641. The next prime is 18218367653. The reversal of 18218367649 is 94676381281.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 94676381281 = 2683 ⋅35287507.

It is a cyclic number.

It is not a de Polignac number, because 18218367649 - 2³ = 18218367641 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18218367649.

It is not an unprimeable number, because it can be changed into a prime (18218367641) 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, 293844609 + ... + 293844670.

It is an arithmetic number, because the mean of its divisors is an integer number (4701514240).

Almost surely, 2^18218367649 is an apocalyptic number.

It is an amenable number.

18218367649 is a deficient number, since it is larger than the sum of its proper divisors (587689311).

18218367649 is an equidigital number, since it uses as much as digits as its factorization.

18218367649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 587689310.

The product of its digits is 3483648, while the sum is 55.

The spelling of 18218367649 in words is "eighteen billion, two hundred eighteen million, three hundred sixty-seven thousand, six hundred forty-nine".