20163905 has 4 divisors (see below), whose sum is σ = 24196692. Its totient is φ = 16131120.

The previous prime is 20163889. The next prime is 20163911. The reversal of 20163905 is 50936102.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4426816 + 15737089 = 2104^2 + 3967^2 .

It is not a de Polignac number, because 20163905 - 2⁴ = 20163889 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2016386 + ... + 2016395.

It is an arithmetic number, because the mean of its divisors is an integer number (6049173).

Almost surely, 2^20163905 is an apocalyptic number.

It is an amenable number.

20163905 is a deficient number, since it is larger than the sum of its proper divisors (4032787).

20163905 is an equidigital number, since it uses as much as digits as its factorization.

20163905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4032786.

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 20163905 is about 4490.4236993852. The cubic root of 20163905 is about 272.1812562415.

The spelling of 20163905 in words is "twenty million, one hundred sixty-three thousand, nine hundred five".