18712520561 has 8 divisors (see below), whose sum is σ = 21396031104. Its totient is φ = 16031583360.

The previous prime is 18712520539. The next prime is 18712520579. The reversal of 18712520561 is 16502521781.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18712520561 - 2¹⁰ = 18712519537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18712520521) 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 7 ways as a sum of consecutive naturals, for example, 627725 + ... + 656858.

It is an arithmetic number, because the mean of its divisors is an integer number (2674503888).

Almost surely, 2^18712520561 is an apocalyptic number.

It is an amenable number.

18712520561 is a deficient number, since it is larger than the sum of its proper divisors (2683510543).

18712520561 is a wasteful number, since it uses less digits than its factorization.

18712520561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1286671.

The product of its (nonzero) digits is 33600, while the sum is 38.

The spelling of 18712520561 in words is "eighteen billion, seven hundred twelve million, five hundred twenty thousand, five hundred sixty-one".