18397121 has 2 divisors, whose sum is σ = 18397122. Its totient is φ = 18397120.

The previous prime is 18397109. The next prime is 18397123. The reversal of 18397121 is 12179381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18395521 + 1600 = 4289^2 + 40^2 .

It is an emirp because it is prime and its reverse (12179381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18397121 - 2¹⁰ = 18396097 is a prime.

It is a super-2 number, since 2×18397121² = 676908122177282, which contains 22 as substring.

Together with 18397123, 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 (18397123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9198560 + 9198561.

It is an arithmetic number, because the mean of its divisors is an integer number (9198561).

Almost surely, 2^18397121 is an apocalyptic number.

It is an amenable number.

18397121 is a deficient number, since it is larger than the sum of its proper divisors (1).

18397121 is an equidigital number, since it uses as much as digits as its factorization.

18397121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 32.

The square root of 18397121 is about 4289.1865196095. The cubic root of 18397121 is about 263.9874544467.

The spelling of 18397121 in words is "eighteen million, three hundred ninety-seven thousand, one hundred twenty-one".