18390397 has 2 divisors, whose sum is σ = 18390398. Its totient is φ = 18390396.

The previous prime is 18390367. The next prime is 18390401. The reversal of 18390397 is 79309381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16597476 + 1792921 = 4074^2 + 1339^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18390397 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18390367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9195198 + 9195199.

It is an arithmetic number, because the mean of its divisors is an integer number (9195199).

Almost surely, 2^18390397 is an apocalyptic number.

It is an amenable number.

18390397 is a deficient number, since it is larger than the sum of its proper divisors (1).

18390397 is an equidigital number, since it uses as much as digits as its factorization.

18390397 is an evil number, because the sum of its binary digits is even.

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

The square root of 18390397 is about 4288.4026163596. The cubic root of 18390397 is about 263.9552887627.

The spelling of 18390397 in words is "eighteen million, three hundred ninety thousand, three hundred ninety-seven".