18390641 has 2 divisors, whose sum is σ = 18390642. Its totient is φ = 18390640.

The previous prime is 18390601. The next prime is 18390643. The reversal of 18390641 is 14609381.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11122225 + 7268416 = 3335^2 + 2696^2 .

It is an emirp because it is prime and its reverse (14609381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18390641 - 2⁶ = 18390577 is a prime.

Together with 18390643, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18390598 and 18390607.

It is not a weakly prime, because it can be changed into another prime (18390643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9195320 + 9195321.

It is an arithmetic number, because the mean of its divisors is an integer number (9195321).

Almost surely, 2^18390641 is an apocalyptic number.

It is an amenable number.

18390641 is a deficient number, since it is larger than the sum of its proper divisors (1).

18390641 is an equidigital number, since it uses as much as digits as its factorization.

18390641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 18390641 is about 4288.4310650866. The cubic root of 18390641 is about 263.9564561256.

The spelling of 18390641 in words is "eighteen million, three hundred ninety thousand, six hundred forty-one".