18663587725 has 12 divisors (see below), whose sum is σ = 23145102324.
Its totient is φ = 14929416320.
The previous prime is 18663587647. The next prime is 18663587773. The reversal of 18663587725 is 52778536681.
It is a happy number.
It can be written as a sum of positive squares in 6 ways, for example, as 7960029961 + 10703557764 = 89219^2 + 103458^2
It is not a de Polignac number, because 18663587725 - 215 = 18663554957 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 18663587725.
It is a congruent number.
It is an unprimeable number.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 279267 + ... + 339583.
It is an arithmetic number, because the mean of its divisors is an integer number (1928758527).
Almost surely, 218663587725 is an apocalyptic number.
It is an amenable number.
18663587725 is a deficient number, since it is larger than the sum of its proper divisors (4481514599).
18663587725 is a wasteful number, since it uses less digits than its factorization.
18663587725 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 72704 (or 72699 counting only the distinct ones).
The product of its digits is 16934400, while the sum is 58.
The spelling of 18663587725 in words is "eighteen billion, six hundred sixty-three million, five hundred eighty-seven thousand, seven hundred twenty-five".