20204391 has 8 divisors (see below), whose sum is σ = 28357120. Its totient is φ = 12760632.

The previous prime is 20204389. The next prime is 20204411. The reversal of 20204391 is 19340202.

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

It is not a de Polignac number, because 20204391 - 2¹ = 20204389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20204311) 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, 177175 + ... + 177288.

It is an arithmetic number, because the mean of its divisors is an integer number (3544640).

Almost surely, 2^20204391 is an apocalyptic number.

20204391 is a deficient number, since it is larger than the sum of its proper divisors (8152729).

20204391 is a wasteful number, since it uses less digits than its factorization.

20204391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 354485.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 20204391 is about 4494.9294766437. The cubic root of 20204391 is about 272.3633004006.

Adding to 20204391 its reverse (19340202), we get a palindrome (39544593).

The spelling of 20204391 in words is "twenty million, two hundred four thousand, three hundred ninety-one".