20168399 has 4 divisors (see below), whose sum is σ = 20181840. Its totient is φ = 20154960.

The previous prime is 20168389. The next prime is 20168411. The reversal of 20168399 is 99386102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20168399 - 2²⁰ = 19119823 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 (20168359) 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 in 3 ways as a sum of consecutive naturals, for example, 4139 + ... + 7580.

It is an arithmetic number, because the mean of its divisors is an integer number (5045460).

Almost surely, 2^20168399 is an apocalyptic number.

20168399 is a deficient number, since it is larger than the sum of its proper divisors (13441).

20168399 is a wasteful number, since it uses less digits than its factorization.

20168399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13440.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 20168399 is about 4490.9240697211. The cubic root of 20168399 is about 272.2014754022.

The spelling of 20168399 in words is "twenty million, one hundred sixty-eight thousand, three hundred ninety-nine".