18441387257 has 4 divisors (see below), whose sum is σ = 18442807140. Its totient is φ = 18439967376.

The previous prime is 18441387241. The next prime is 18441387271. The reversal of 18441387257 is 75278314481.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2621030416 + 15820356841 = 51196^2 + 125779^2 .

It is a cyclic number.

It is not a de Polignac number, because 18441387257 - 2⁴ = 18441387241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18441387277) 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, 690278 + ... + 716495.

It is an arithmetic number, because the mean of its divisors is an integer number (4610701785).

Almost surely, 2^18441387257 is an apocalyptic number.

It is an amenable number.

18441387257 is a deficient number, since it is larger than the sum of its proper divisors (1419883).

18441387257 is a wasteful number, since it uses less digits than its factorization.

18441387257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1419882.

The product of its digits is 1505280, while the sum is 50.

The spelling of 18441387257 in words is "eighteen billion, four hundred forty-one million, three hundred eighty-seven thousand, two hundred fifty-seven".