19979243 has 2 divisors, whose sum is σ = 19979244. Its totient is φ = 19979242.

The previous prime is 19979237. The next prime is 19979257. The reversal of 19979243 is 34297991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19979243 - 2⁴ = 19979227 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 19979194 and 19979203.

It is not a weakly prime, because it can be changed into another prime (19979213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9989621 + 9989622.

It is an arithmetic number, because the mean of its divisors is an integer number (9989622).

Almost surely, 2^19979243 is an apocalyptic number.

19979243 is a deficient number, since it is larger than the sum of its proper divisors (1).

19979243 is an equidigital number, since it uses as much as digits as its factorization.

19979243 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 122472, while the sum is 44.

The square root of 19979243 is about 4469.8146494010. The cubic root of 19979243 is about 271.3478238768.

The spelling of 19979243 in words is "nineteen million, nine hundred seventy-nine thousand, two hundred forty-three".