18138437 has 2 divisors, whose sum is σ = 18138438. Its totient is φ = 18138436.

The previous prime is 18138409. The next prime is 18138443. The reversal of 18138437 is 73483181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15319396 + 2819041 = 3914^2 + 1679^2 .

It is an emirp because it is prime and its reverse (73483181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18138437 - 2¹⁴ = 18122053 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18138397 and 18138406.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18138487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9069218 + 9069219.

It is an arithmetic number, because the mean of its divisors is an integer number (9069219).

Almost surely, 2^18138437 is an apocalyptic number.

It is an amenable number.

18138437 is a deficient number, since it is larger than the sum of its proper divisors (1).

18138437 is an equidigital number, since it uses as much as digits as its factorization.

18138437 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 35.

The square root of 18138437 is about 4258.9243947269. The cubic root of 18138437 is about 262.7442901973.

The spelling of 18138437 in words is "eighteen million, one hundred thirty-eight thousand, four hundred thirty-seven".