18523047949 has 4 divisors (see below), whose sum is σ = 21169197664. Its totient is φ = 15876898236.

The previous prime is 18523047947. The next prime is 18523047967. The reversal of 18523047949 is 94974032581.

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: 94974032581 = 59069 ⋅1607849.

It is a cyclic number.

It is not a de Polignac number, because 18523047949 - 2¹ = 18523047947 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18523047896 and 18523047905.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18523047943) 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, 1323074847 + ... + 1323074860.

It is an arithmetic number, because the mean of its divisors is an integer number (5292299416).

Almost surely, 2^18523047949 is an apocalyptic number.

It is an amenable number.

18523047949 is a deficient number, since it is larger than the sum of its proper divisors (2646149715).

18523047949 is an equidigital number, since it uses as much as digits as its factorization.

18523047949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2646149714.

The product of its (nonzero) digits is 2177280, while the sum is 52.

The spelling of 18523047949 in words is "eighteen billion, five hundred twenty-three million, forty-seven thousand, nine hundred forty-nine".