18969949 has 2 divisors, whose sum is σ = 18969950. Its totient is φ = 18969948.

The previous prime is 18969947. The next prime is 18969959. The reversal of 18969949 is 94996981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16867449 + 2102500 = 4107^2 + 1450^2 .

It is a cyclic number.

It is not a de Polignac number, because 18969949 - 2¹ = 18969947 is a prime.

Together with 18969947, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 18969949.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18969947) 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 as a sum of consecutive naturals, namely, 9484974 + 9484975.

It is an arithmetic number, because the mean of its divisors is an integer number (9484975).

Almost surely, 2^18969949 is an apocalyptic number.

It is an amenable number.

18969949 is a deficient number, since it is larger than the sum of its proper divisors (1).

18969949 is an equidigital number, since it uses as much as digits as its factorization.

18969949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1259712, while the sum is 55.

The square root of 18969949 is about 4355.4504933474. The cubic root of 18969949 is about 266.6994096947.

The spelling of 18969949 in words is "eighteen million, nine hundred sixty-nine thousand, nine hundred forty-nine".