18947849 has 2 divisors, whose sum is σ = 18947850. Its totient is φ = 18947848.

The previous prime is 18947827. The next prime is 18947857. The reversal of 18947849 is 94874981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13690000 + 5257849 = 3700^2 + 2293^2 .

It is a cyclic number.

It is not a de Polignac number, because 18947849 - 2¹⁶ = 18882313 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 18947797 and 18947806.

It is not a weakly prime, because it can be changed into another prime (18947879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9473924 + 9473925.

It is an arithmetic number, because the mean of its divisors is an integer number (9473925).

Almost surely, 2^18947849 is an apocalyptic number.

It is an amenable number.

18947849 is a deficient number, since it is larger than the sum of its proper divisors (1).

18947849 is an equidigital number, since it uses as much as digits as its factorization.

18947849 is an evil number, because the sum of its binary digits is even.

The product of its digits is 580608, while the sum is 50.

The square root of 18947849 is about 4352.9127030070. The cubic root of 18947849 is about 266.5958011347.

The spelling of 18947849 in words is "eighteen million, nine hundred forty-seven thousand, eight hundred forty-nine".