2178643 has 2 divisors, whose sum is σ = 2178644. Its totient is φ = 2178642.

The previous prime is 2178641. The next prime is 2178647. The reversal of 2178643 is 3468712.

2178643 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2178643 - 2¹ = 2178641 is a prime.

Together with 2178641, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2178641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1089321 + 1089322.

It is an arithmetic number, because the mean of its divisors is an integer number (1089322).

2^2178643 is an apocalyptic number.

2178643 is a deficient number, since it is larger than the sum of its proper divisors (1).

2178643 is an equidigital number, since it uses as much as digits as its factorization.

2178643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 31.

The square root of 2178643 is about 1476.0226963025. The cubic root of 2178643 is about 129.6369158605.

The spelling of 2178643 in words is "two million, one hundred seventy-eight thousand, six hundred forty-three".