20305407 has 4 divisors (see below), whose sum is σ = 27073880. Its totient is φ = 13536936.

The previous prime is 20305391. The next prime is 20305409. The reversal of 20305407 is 70450302.

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 20305407 - 2⁴ = 20305391 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 (20305409) 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, 3384232 + ... + 3384237.

It is an arithmetic number, because the mean of its divisors is an integer number (6768470).

Almost surely, 2^20305407 is an apocalyptic number.

20305407 is a deficient number, since it is larger than the sum of its proper divisors (6768473).

20305407 is an equidigital number, since it uses as much as digits as its factorization.

20305407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6768472.

The product of its (nonzero) digits is 840, while the sum is 21.

The square root of 20305407 is about 4506.1521279247. The cubic root of 20305407 is about 272.8164580947.

Adding to 20305407 its reverse (70450302), we get a palindrome (90755709).

The spelling of 20305407 in words is "twenty million, three hundred five thousand, four hundred seven".