20804587 has 4 divisors (see below), whose sum is σ = 20821680. Its totient is φ = 20787496.

The previous prime is 20804573. The next prime is 20804591. The reversal of 20804587 is 78540802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20804587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20804527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6568 + ... + 9205.

It is an arithmetic number, because the mean of its divisors is an integer number (5205420).

Almost surely, 2^20804587 is an apocalyptic number.

20804587 is a deficient number, since it is larger than the sum of its proper divisors (17093).

20804587 is a wasteful number, since it uses less digits than its factorization.

20804587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17092.

The product of its (nonzero) digits is 17920, while the sum is 34.

The square root of 20804587 is about 4561.2045558164. The cubic root of 20804587 is about 275.0339880856.

The spelling of 20804587 in words is "twenty million, eight hundred four thousand, five hundred eighty-seven".