18649956557 has 4 divisors (see below), whose sum is σ = 18653728416. Its totient is φ = 18646184700.

The previous prime is 18649956553. The next prime is 18649956583. The reversal of 18649956557 is 75565994681.

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.

It is a cyclic number.

It is not a de Polignac number, because 18649956557 - 2² = 18649956553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18649956493 and 18649956502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18649956553) 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 3 ways as a sum of consecutive naturals, for example, 1878503 + ... + 1888404.

It is an arithmetic number, because the mean of its divisors is an integer number (4663432104).

Almost surely, 2^18649956557 is an apocalyptic number.

It is an amenable number.

18649956557 is a deficient number, since it is larger than the sum of its proper divisors (3771859).

18649956557 is an equidigital number, since it uses as much as digits as its factorization.

18649956557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3771858.

The product of its digits is 81648000, while the sum is 65.

The spelling of 18649956557 in words is "eighteen billion, six hundred forty-nine million, nine hundred fifty-six thousand, five hundred fifty-seven".