20163999 has 4 divisors (see below), whose sum is σ = 26885336. Its totient is φ = 13442664.

The previous prime is 20163991. The next prime is 20164003. The reversal of 20163999 is 99936102.

It is a happy number.

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

It is not a de Polignac number, because 20163999 - 2³ = 20163991 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 (20163991) 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, 3360664 + ... + 3360669.

It is an arithmetic number, because the mean of its divisors is an integer number (6721334).

Almost surely, 2^20163999 is an apocalyptic number.

20163999 is a deficient number, since it is larger than the sum of its proper divisors (6721337).

20163999 is an equidigital number, since it uses as much as digits as its factorization.

20163999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6721336.

The product of its (nonzero) digits is 26244, while the sum is 39.

The square root of 20163999 is about 4490.4341660913. The cubic root of 20163999 is about 272.1816791920.

The spelling of 20163999 in words is "twenty million, one hundred sixty-three thousand, nine hundred ninety-nine".