18689945 has 4 divisors (see below), whose sum is σ = 22427940. Its totient is φ = 14951952.

The previous prime is 18689941. The next prime is 18689947. The reversal of 18689945 is 54998681.

It is a happy number.

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 4227136 + 14462809 = 2056^2 + 3803^2 .

It is a cyclic number.

It is not a de Polignac number, because 18689945 - 2² = 18689941 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 18689893 and 18689902.

It is not an unprimeable number, because it can be changed into a prime (18689941) 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, 1868990 + ... + 1868999.

It is an arithmetic number, because the mean of its divisors is an integer number (5606985).

Almost surely, 2^18689945 is an apocalyptic number.

It is an amenable number.

18689945 is a deficient number, since it is larger than the sum of its proper divisors (3737995).

18689945 is an equidigital number, since it uses as much as digits as its factorization.

18689945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3737994.

The product of its digits is 622080, while the sum is 50.

The square root of 18689945 is about 4323.1869032000. The cubic root of 18689945 is about 265.3807035545.

The spelling of 18689945 in words is "eighteen million, six hundred eighty-nine thousand, nine hundred forty-five".