20305081 has 4 divisors (see below), whose sum is σ = 20737152. Its totient is φ = 19873012.

The previous prime is 20305079. The next prime is 20305097. The reversal of 20305081 is 18050302.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 20305081 - 2¹ = 20305079 is a prime.

It is a super-2 number, since 2×20305081² = 824592628833122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20305781) 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, 215965 + ... + 216058.

It is an arithmetic number, because the mean of its divisors is an integer number (5184288).

Almost surely, 2^20305081 is an apocalyptic number.

It is an amenable number.

20305081 is a deficient number, since it is larger than the sum of its proper divisors (432071).

20305081 is an equidigital number, since it uses as much as digits as its factorization.

20305081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432070.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 20305081 is about 4506.1159550105. The cubic root of 20305081 is about 272.8149980789.

Adding to 20305081 its reverse (18050302), we get a palindrome (38355383).

The spelling of 20305081 in words is "twenty million, three hundred five thousand, eighty-one".