168641009 has 4 divisors (see below), whose sum is σ = 168668016. Its totient is φ = 168614004.

The previous prime is 168640987. The next prime is 168641021. The reversal of 168641009 is 900146861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 900146861 = 3257 ⋅276373.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-168641009 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 168641009.

It is not an unprimeable number, because it can be changed into a prime (168641059) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1202 + ... + 18404.

It is an arithmetic number, because the mean of its divisors is an integer number (42167004).

Almost surely, 2^168641009 is an apocalyptic number.

It is an amenable number.

168641009 is a deficient number, since it is larger than the sum of its proper divisors (27007).

168641009 is an equidigital number, since it uses as much as digits as its factorization.

168641009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27006.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 168641009 is about 12986.1853136323. The cubic root of 168641009 is about 552.4857284248.

The spelling of 168641009 in words is "one hundred sixty-eight million, six hundred forty-one thousand, nine".