18155897 has 2 divisors, whose sum is σ = 18155898. Its totient is φ = 18155896.

The previous prime is 18155873. The next prime is 18155899. The reversal of 18155897 is 79855181.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17147881 + 1008016 = 4141^2 + 1004^2 .

It is a cyclic number.

It is not a de Polignac number, because 18155897 - 2²⁴ = 1378681 is a prime.

Together with 18155899, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18155899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9077948 + 9077949.

It is an arithmetic number, because the mean of its divisors is an integer number (9077949).

Almost surely, 2^18155897 is an apocalyptic number.

It is an amenable number.

18155897 is a deficient number, since it is larger than the sum of its proper divisors (1).

18155897 is an equidigital number, since it uses as much as digits as its factorization.

18155897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 100800, while the sum is 44.

The square root of 18155897 is about 4260.9737150093. The cubic root of 18155897 is about 262.8285687585.

The spelling of 18155897 in words is "eighteen million, one hundred fifty-five thousand, eight hundred ninety-seven".