18642641 has 2 divisors, whose sum is σ = 18642642. Its totient is φ = 18642640.

The previous prime is 18642623. The next prime is 18642647. The reversal of 18642641 is 14624681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13535041 + 5107600 = 3679^2 + 2260^2 .

It is a cyclic number.

It is not a de Polignac number, because 18642641 - 2¹⁸ = 18380497 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18642598 and 18642607.

It is not a weakly prime, because it can be changed into another prime (18642647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9321320 + 9321321.

It is an arithmetic number, because the mean of its divisors is an integer number (9321321).

Almost surely, 2^18642641 is an apocalyptic number.

It is an amenable number.

18642641 is a deficient number, since it is larger than the sum of its proper divisors (1).

18642641 is an equidigital number, since it uses as much as digits as its factorization.

18642641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9216, while the sum is 32.

The square root of 18642641 is about 4317.7124730579. The cubic root of 18642641 is about 265.1566227330.

The spelling of 18642641 in words is "eighteen million, six hundred forty-two thousand, six hundred forty-one".