18722173 has 2 divisors, whose sum is σ = 18722174. Its totient is φ = 18722172.

The previous prime is 18722159. The next prime is 18722183. The reversal of 18722173 is 37122781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17994564 + 727609 = 4242^2 + 853^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18722173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18722113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9361086 + 9361087.

It is an arithmetic number, because the mean of its divisors is an integer number (9361087).

Almost surely, 2^18722173 is an apocalyptic number.

It is an amenable number.

18722173 is a deficient number, since it is larger than the sum of its proper divisors (1).

18722173 is an equidigital number, since it uses as much as digits as its factorization.

18722173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4704, while the sum is 31.

The square root of 18722173 is about 4326.9126406712. The cubic root of 18722173 is about 265.5331523369.

The spelling of 18722173 in words is "eighteen million, seven hundred twenty-two thousand, one hundred seventy-three".