18537986257 has 4 divisors (see below), whose sum is σ = 21186270016. Its totient is φ = 15889702500.

The previous prime is 18537986249. The next prime is 18537986279. The reversal of 18537986257 is 75268973581.

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: 75268973581 = 47 ⋅1601467523.

It is not a de Polignac number, because 18537986257 - 2³ = 18537986249 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18537986195 and 18537986204.

It is not an unprimeable number, because it can be changed into a prime (18537989257) 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, 1324141869 + ... + 1324141882.

It is an arithmetic number, because the mean of its divisors is an integer number (5296567504).

Almost surely, 2^18537986257 is an apocalyptic number.

It is an amenable number.

18537986257 is a deficient number, since it is larger than the sum of its proper divisors (2648283759).

18537986257 is an equidigital number, since it uses as much as digits as its factorization.

18537986257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2648283758.

The product of its digits is 25401600, while the sum is 61.

The spelling of 18537986257 in words is "eighteen billion, five hundred thirty-seven million, nine hundred eighty-six thousand, two hundred fifty-seven".