18537997 has 2 divisors, whose sum is σ = 18537998. Its totient is φ = 18537996.

The previous prime is 18537991. The next prime is 18538001. The reversal of 18537997 is 79973581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18412681 + 125316 = 4291^2 + 354^2 .

It is a cyclic number.

It is not a de Polignac number, because 18537997 - 2¹⁵ = 18505229 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18537997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18537991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9268998 + 9268999.

It is an arithmetic number, because the mean of its divisors is an integer number (9268999).

Almost surely, 2^18537997 is an apocalyptic number.

It is an amenable number.

18537997 is a deficient number, since it is larger than the sum of its proper divisors (1).

18537997 is an equidigital number, since it uses as much as digits as its factorization.

18537997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 476280, while the sum is 49.

The square root of 18537997 is about 4305.5774293351. The cubic root of 18537997 is about 264.6595699767.

The spelling of 18537997 in words is "eighteen million, five hundred thirty-seven thousand, nine hundred ninety-seven".