18645643 has 2 divisors, whose sum is σ = 18645644. Its totient is φ = 18645642.

The previous prime is 18645629. The next prime is 18645673. The reversal of 18645643 is 34654681.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18645643 - 2⁹ = 18645131 is a prime.

It is not a weakly prime, because it can be changed into another prime (18645673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9322821 + 9322822.

It is an arithmetic number, because the mean of its divisors is an integer number (9322822).

Almost surely, 2^18645643 is an apocalyptic number.

18645643 is a deficient number, since it is larger than the sum of its proper divisors (1).

18645643 is an equidigital number, since it uses as much as digits as its factorization.

18645643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 37.

The square root of 18645643 is about 4318.0600968490. The cubic root of 18645643 is about 265.1708545767.

The spelling of 18645643 in words is "eighteen million, six hundred forty-five thousand, six hundred forty-three".