18913289 has 2 divisors, whose sum is σ = 18913290. Its totient is φ = 18913288.

The previous prime is 18913277. The next prime is 18913369. The reversal of 18913289 is 98231981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16687225 + 2226064 = 4085^2 + 1492^2 .

It is an emirp because it is prime and its reverse (98231981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18913289 - 2⁴ = 18913273 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18913589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9456644 + 9456645.

It is an arithmetic number, because the mean of its divisors is an integer number (9456645).

Almost surely, 2^18913289 is an apocalyptic number.

It is an amenable number.

18913289 is a deficient number, since it is larger than the sum of its proper divisors (1).

18913289 is an equidigital number, since it uses as much as digits as its factorization.

18913289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 41.

The square root of 18913289 is about 4348.9411354949. The cubic root of 18913289 is about 266.4336163529.

The spelling of 18913289 in words is "eighteen million, nine hundred thirteen thousand, two hundred eighty-nine".