20304661 has 8 divisors (see below), whose sum is σ = 21901880. Its totient is φ = 18712512.

The previous prime is 20304619. The next prime is 20304667. The reversal of 20304661 is 16640302.

It can be written as a sum of positive squares in 4 ways, for example, as 1425636 + 18879025 = 1194^2 + 4345^2 .

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

It is a de Polignac number, because none of the positive numbers 2^k-20304661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20304667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13495 + ... + 14923.

It is an arithmetic number, because the mean of its divisors is an integer number (2737735).

Almost surely, 2^20304661 is an apocalyptic number.

It is an amenable number.

20304661 is a deficient number, since it is larger than the sum of its proper divisors (1597219).

20304661 is a wasteful number, since it uses less digits than its factorization.

20304661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2535.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 20304661 is about 4506.0693514415. The cubic root of 20304661 is about 272.8131170540.

Adding to 20304661 its reverse (16640302), we get a palindrome (36944963).

The spelling of 20304661 in words is "twenty million, three hundred four thousand, six hundred sixty-one".