18930397 has 4 divisors (see below), whose sum is σ = 19392156. Its totient is φ = 18468640.

The previous prime is 18930377. The next prime is 18930407. The reversal of 18930397 is 79303981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79303981 = 179 ⋅443039.

It can be written as a sum of positive squares in 2 ways, for example, as 10830681 + 8099716 = 3291^2 + 2846^2 .

It is a cyclic number.

It is not a de Polignac number, because 18930397 - 2⁷ = 18930269 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 (18930377) 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 in 3 ways as a sum of consecutive naturals, for example, 230818 + ... + 230899.

It is an arithmetic number, because the mean of its divisors is an integer number (4848039).

Almost surely, 2^18930397 is an apocalyptic number.

It is an amenable number.

18930397 is a deficient number, since it is larger than the sum of its proper divisors (461759).

18930397 is an equidigital number, since it uses as much as digits as its factorization.

18930397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 461758.

The product of its (nonzero) digits is 40824, while the sum is 40.

The square root of 18930397 is about 4350.9076064656. The cubic root of 18930397 is about 266.5139262458.

It can be divided in two parts, 1 and 8930397, that added together give a palindrome (8930398).

The spelling of 18930397 in words is "eighteen million, nine hundred thirty thousand, three hundred ninety-seven".