18918437 has 2 divisors, whose sum is σ = 18918438. Its totient is φ = 18918436.

The previous prime is 18918421. The next prime is 18918451. The reversal of 18918437 is 73481981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16008001 + 2910436 = 4001^2 + 1706^2 .

It is a cyclic number.

It is not a de Polignac number, because 18918437 - 2⁴ = 18918421 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18918394 and 18918403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18918457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9459218 + 9459219.

It is an arithmetic number, because the mean of its divisors is an integer number (9459219).

Almost surely, 2^18918437 is an apocalyptic number.

It is an amenable number.

18918437 is a deficient number, since it is larger than the sum of its proper divisors (1).

18918437 is an equidigital number, since it uses as much as digits as its factorization.

18918437 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 41.

The square root of 18918437 is about 4349.5329634341. The cubic root of 18918437 is about 266.4577876438.

The spelling of 18918437 in words is "eighteen million, nine hundred eighteen thousand, four hundred thirty-seven".