20051305 has 4 divisors (see below), whose sum is σ = 24061572. Its totient is φ = 16041040.

The previous prime is 20051303. The next prime is 20051309. The reversal of 20051305 is 50315002.

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 14462809 + 5588496 = 3803^2 + 2364^2 .

It is not a de Polignac number, because 20051305 - 2¹ = 20051303 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20051303) 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, 2005126 + ... + 2005135.

It is an arithmetic number, because the mean of its divisors is an integer number (6015393).

Almost surely, 2^20051305 is an apocalyptic number.

It is an amenable number.

20051305 is a deficient number, since it is larger than the sum of its proper divisors (4010267).

20051305 is an equidigital number, since it uses as much as digits as its factorization.

20051305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4010266.

The product of its (nonzero) digits is 150, while the sum is 16.

The square root of 20051305 is about 4477.8683544740. The cubic root of 20051305 is about 271.6736687988.

Adding to 20051305 its reverse (50315002), we get a palindrome (70366307).

The spelling of 20051305 in words is "twenty million, fifty-one thousand, three hundred five".