16641997 has 8 divisors (see below), whose sum is σ = 17659512. Its totient is φ = 15628800.

The previous prime is 16641991. The next prime is 16642001. The reversal of 16641997 is 79914661.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 6280036 + 10361961 = 2506^2 + 3219^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 16641997 - 2¹⁹ = 16117709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16641991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10497 + ... + 11977.

It is an arithmetic number, because the mean of its divisors is an integer number (2207439).

Almost surely, 2^16641997 is an apocalyptic number.

16641997 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

16641997 is a deficient number, since it is larger than the sum of its proper divisors (1017515).

16641997 is a wasteful number, since it uses less digits than its factorization.

16641997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2159.

The product of its digits is 81648, while the sum is 43.

The square root of 16641997 is about 4079.4603809818. The cubic root of 16641997 is about 255.3103845756.

The spelling of 16641997 in words is "sixteen million, six hundred forty-one thousand, nine hundred ninety-seven".