19812643 has 4 divisors (see below), whose sum is σ = 19955320. Its totient is φ = 19669968.

The previous prime is 19812607. The next prime is 19812677. The reversal of 19812643 is 34621891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34621891 = 101 ⋅342791.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19812643 is a prime.

It is a super-3 number, since 3×19812643³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19812599 and 19812608.

It is not an unprimeable number, because it can be changed into a prime (19812343) 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 in 3 ways as a sum of consecutive naturals, for example, 71130 + ... + 71407.

It is an arithmetic number, because the mean of its divisors is an integer number (4988830).

Almost surely, 2^19812643 is an apocalyptic number.

19812643 is a deficient number, since it is larger than the sum of its proper divisors (142677).

19812643 is a wasteful number, since it uses less digits than its factorization.

19812643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142676.

The product of its digits is 10368, while the sum is 34.

The square root of 19812643 is about 4451.1395170226. The cubic root of 19812643 is about 270.5914924726.

It can be divided in two parts, 1981 and 2643, that added together give a square (4624 = 68²).

The spelling of 19812643 in words is "nineteen million, eight hundred twelve thousand, six hundred forty-three".