19878643 has 4 divisors (see below), whose sum is σ = 19912000. Its totient is φ = 19845288.

The previous prime is 19878641. The next prime is 19878653. The reversal of 19878643 is 34687891.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19878643 - 2¹ = 19878641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19878593 and 19878602.

It is not an unprimeable number, because it can be changed into a prime (19878641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15768 + ... + 16981.

It is an arithmetic number, because the mean of its divisors is an integer number (4978000).

Almost surely, 2^19878643 is an apocalyptic number.

19878643 is a deficient number, since it is larger than the sum of its proper divisors (33357).

19878643 is an equidigital number, since it uses as much as digits as its factorization.

19878643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33356.

The product of its digits is 290304, while the sum is 46.

The square root of 19878643 is about 4458.5471849023. The cubic root of 19878643 is about 270.8916248074.

The spelling of 19878643 in words is "nineteen million, eight hundred seventy-eight thousand, six hundred forty-three".