18561560947 has 4 divisors (see below), whose sum is σ = 19368585360. Its totient is φ = 17754536536.

The previous prime is 18561560939. The next prime is 18561560981. The reversal of 18561560947 is 74906516581.

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

It is a cyclic number.

It is not a de Polignac number, because 18561560947 - 2³ = 18561560939 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18561560894 and 18561560903.

It is not an unprimeable number, because it can be changed into a prime (18561564947) 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, 403512172 + ... + 403512217.

It is an arithmetic number, because the mean of its divisors is an integer number (4842146340).

Almost surely, 2^18561560947 is an apocalyptic number.

18561560947 is a deficient number, since it is larger than the sum of its proper divisors (807024413).

18561560947 is an equidigital number, since it uses as much as digits as its factorization.

18561560947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 807024412.

The product of its (nonzero) digits is 1814400, while the sum is 52.

The spelling of 18561560947 in words is "eighteen billion, five hundred sixty-one million, five hundred sixty thousand, nine hundred forty-seven".