18657641 has 4 divisors (see below), whose sum is σ = 18673284. Its totient is φ = 18642000.

The previous prime is 18657599. The next prime is 18657647. The reversal of 18657641 is 14675681.

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 133225 + 18524416 = 365^2 + 4304^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18657641 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 18657595 and 18657604.

It is not an unprimeable number, because it can be changed into a prime (18657647) 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, 5870 + ... + 8471.

It is an arithmetic number, because the mean of its divisors is an integer number (4668321).

Almost surely, 2^18657641 is an apocalyptic number.

It is an amenable number.

18657641 is a deficient number, since it is larger than the sum of its proper divisors (15643).

18657641 is a wasteful number, since it uses less digits than its factorization.

18657641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15642.

The product of its digits is 40320, while the sum is 38.

The square root of 18657641 is about 4319.4491546955. The cubic root of 18657641 is about 265.2277192956.

The spelling of 18657641 in words is "eighteen million, six hundred fifty-seven thousand, six hundred forty-one".