18722947 has 2 divisors, whose sum is σ = 18722948. Its totient is φ = 18722946.

The previous prime is 18722941. The next prime is 18722981. The reversal of 18722947 is 74922781.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18722947 - 2¹⁹ = 18198659 is a prime.

It is not a weakly prime, because it can be changed into another prime (18722941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9361473 + 9361474.

It is an arithmetic number, because the mean of its divisors is an integer number (9361474).

Almost surely, 2^18722947 is an apocalyptic number.

18722947 is a deficient number, since it is larger than the sum of its proper divisors (1).

18722947 is an equidigital number, since it uses as much as digits as its factorization.

18722947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56448, while the sum is 40.

The square root of 18722947 is about 4327.0020799625. The cubic root of 18722947 is about 265.5368114532.

The spelling of 18722947 in words is "eighteen million, seven hundred twenty-two thousand, nine hundred forty-seven".