20305906 has 8 divisors (see below), whose sum is σ = 31201884. Its totient is φ = 9905280.

The previous prime is 20305897. The next prime is 20305907. The reversal of 20305906 is 60950302.

It can be written as a sum of positive squares in 2 ways, for example, as 17098225 + 3207681 = 4135^2 + 1791^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (20305907) 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, 123735 + ... + 123898.

Almost surely, 2^20305906 is an apocalyptic number.

20305906 is a deficient number, since it is larger than the sum of its proper divisors (10895978).

20305906 is a wasteful number, since it uses less digits than its factorization.

20305906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247676.

The product of its (nonzero) digits is 1620, while the sum is 25.

The square root of 20305906 is about 4506.2074963321. The cubic root of 20305906 is about 272.8186928738.

The spelling of 20305906 in words is "twenty million, three hundred five thousand, nine hundred six".