18051997 has 2 divisors, whose sum is σ = 18051998. Its totient is φ = 18051996.

The previous prime is 18051989. The next prime is 18052003. The reversal of 18051997 is 79915081.

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., 12880921 + 5171076 = 3589^2 + 2274^2 .

It is a cyclic number.

It is not a de Polignac number, because 18051997 - 2³ = 18051989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18055997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9025998 + 9025999.

It is an arithmetic number, because the mean of its divisors is an integer number (9025999).

Almost surely, 2^18051997 is an apocalyptic number.

It is an amenable number.

18051997 is a deficient number, since it is larger than the sum of its proper divisors (1).

18051997 is an equidigital number, since it uses as much as digits as its factorization.

18051997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 40.

The square root of 18051997 is about 4248.7641732626. The cubic root of 18051997 is about 262.3262499475.

The spelling of 18051997 in words is "eighteen million, fifty-one thousand, nine hundred ninety-seven".