19678643 has 2 divisors, whose sum is σ = 19678644. Its totient is φ = 19678642.

The previous prime is 19678621. The next prime is 19678669. The reversal of 19678643 is 34687691.

It is a weak prime.

It is an emirp because it is prime and its reverse (34687691) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19678643 - 2¹⁴ = 19662259 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19678594 and 19678603.

It is not a weakly prime, because it can be changed into another prime (19678613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9839321 + 9839322.

It is an arithmetic number, because the mean of its divisors is an integer number (9839322).

Almost surely, 2^19678643 is an apocalyptic number.

19678643 is a deficient number, since it is larger than the sum of its proper divisors (1).

19678643 is an equidigital number, since it uses as much as digits as its factorization.

19678643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 44.

The square root of 19678643 is about 4436.0616542154. The cubic root of 19678643 is about 269.9800762619.

The spelling of 19678643 in words is "nineteen million, six hundred seventy-eight thousand, six hundred forty-three".