18708973 has 4 divisors (see below), whose sum is σ = 19354140. Its totient is φ = 18063808.

The previous prime is 18708971. The next prime is 18708979. The reversal of 18708973 is 37980781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 37980781 = 4127 ⋅9203.

It can be written as a sum of positive squares in 2 ways, for example, as 5004169 + 13704804 = 2237^2 + 3702^2 .

It is a cyclic number.

It is not a de Polignac number, because 18708973 - 2¹ = 18708971 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18708971) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 322540 + ... + 322597.

It is an arithmetic number, because the mean of its divisors is an integer number (4838535).

Almost surely, 2^18708973 is an apocalyptic number.

It is an amenable number.

18708973 is a deficient number, since it is larger than the sum of its proper divisors (645167).

18708973 is an equidigital number, since it uses as much as digits as its factorization.

18708973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 645166.

The product of its (nonzero) digits is 84672, while the sum is 43.

The square root of 18708973 is about 4325.3870347057. The cubic root of 18708973 is about 265.4707332706.

The spelling of 18708973 in words is "eighteen million, seven hundred eight thousand, nine hundred seventy-three".