19979543 has 4 divisors (see below), whose sum is σ = 20081160. Its totient is φ = 19877928.

The previous prime is 19979537. The next prime is 19979549. The reversal of 19979543 is 34597991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34597991 = 1523 ⋅22717.

It is an interprime number because it is at equal distance from previous prime (19979537) and next prime (19979549).

It is a cyclic number.

It is not a de Polignac number, because 19979543 - 2⁴ = 19979527 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19979549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50513 + ... + 50906.

It is an arithmetic number, because the mean of its divisors is an integer number (5020290).

Almost surely, 2^19979543 is an apocalyptic number.

19979543 is a deficient number, since it is larger than the sum of its proper divisors (101617).

19979543 is a wasteful number, since it uses less digits than its factorization.

19979543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101616.

The product of its digits is 306180, while the sum is 47.

The square root of 19979543 is about 4469.8482077135. The cubic root of 19979543 is about 271.3491820186.

The spelling of 19979543 in words is "nineteen million, nine hundred seventy-nine thousand, five hundred forty-three".