16687997 has 2 divisors, whose sum is σ = 16687998. Its totient is φ = 16687996.

The previous prime is 16687939. The next prime is 16688003. The reversal of 16687997 is 79978661.

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., 11909401 + 4778596 = 3451^2 + 2186^2 .

It is a cyclic number.

It is not a de Polignac number, because 16687997 - 2⁶ = 16687933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16687597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8343998 + 8343999.

It is an arithmetic number, because the mean of its divisors is an integer number (8343999).

Almost surely, 2^16687997 is an apocalyptic number.

It is an amenable number.

16687997 is a deficient number, since it is larger than the sum of its proper divisors (1).

16687997 is an equidigital number, since it uses as much as digits as its factorization.

16687997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1143072, while the sum is 53.

The square root of 16687997 is about 4085.0944909512. The cubic root of 16687997 is about 255.5454019140.

The spelling of 16687997 in words is "sixteen million, six hundred eighty-seven thousand, nine hundred ninety-seven".