18361997 has 2 divisors, whose sum is σ = 18361998. Its totient is φ = 18361996.

The previous prime is 18361991. The next prime is 18362033. The reversal of 18361997 is 79916381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13756681 + 4605316 = 3709^2 + 2146^2 .

It is a cyclic number.

It is not a de Polignac number, because 18361997 - 2¹⁶ = 18296461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18361991) 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, 9180998 + 9180999.

It is an arithmetic number, because the mean of its divisors is an integer number (9180999).

Almost surely, 2^18361997 is an apocalyptic number.

It is an amenable number.

18361997 is a deficient number, since it is larger than the sum of its proper divisors (1).

18361997 is an equidigital number, since it uses as much as digits as its factorization.

18361997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 44.

The square root of 18361997 is about 4285.0900807334. The cubic root of 18361997 is about 263.8193447636.

The spelling of 18361997 in words is "eighteen million, three hundred sixty-one thousand, nine hundred ninety-seven".