18640001 has 2 divisors, whose sum is σ = 18640002. Its totient is φ = 18640000.

The previous prime is 18639991. The next prime is 18640009. The reversal of 18640001 is 10004681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14938225 + 3701776 = 3865^2 + 1924^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18640001 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18640009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9320000 + 9320001.

It is an arithmetic number, because the mean of its divisors is an integer number (9320001).

Almost surely, 2^18640001 is an apocalyptic number.

It is an amenable number.

18640001 is a deficient number, since it is larger than the sum of its proper divisors (1).

18640001 is an equidigital number, since it uses as much as digits as its factorization.

18640001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 18640001 is about 4317.4067447948. The cubic root of 18640001 is about 265.1441057917.

Adding to 18640001 its reverse (10004681), we get a palindrome (28644682).

The spelling of 18640001 in words is "eighteen million, six hundred forty thousand, one".