18291397 has 2 divisors, whose sum is σ = 18291398. Its totient is φ = 18291396.

The previous prime is 18291359. The next prime is 18291419. The reversal of 18291397 is 79319281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13771521 + 4519876 = 3711^2 + 2126^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18291397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18291347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9145698 + 9145699.

It is an arithmetic number, because the mean of its divisors is an integer number (9145699).

Almost surely, 2^18291397 is an apocalyptic number.

It is an amenable number.

18291397 is a deficient number, since it is larger than the sum of its proper divisors (1).

18291397 is an equidigital number, since it uses as much as digits as its factorization.

18291397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 40.

The square root of 18291397 is about 4276.8442805414. The cubic root of 18291397 is about 263.4807910269.

The spelling of 18291397 in words is "eighteen million, two hundred ninety-one thousand, three hundred ninety-seven".