20904591 has 8 divisors (see below), whose sum is σ = 28057984. Its totient is φ = 13843800.

The previous prime is 20904589. The next prime is 20904599. The reversal of 20904591 is 19540902.

It is a happy number.

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

It is not a de Polignac number, because 20904591 - 2¹ = 20904589 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 (20904599) 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 7 ways as a sum of consecutive naturals, for example, 22621 + ... + 23526.

It is an arithmetic number, because the mean of its divisors is an integer number (3507248).

Almost surely, 2^20904591 is an apocalyptic number.

20904591 is a deficient number, since it is larger than the sum of its proper divisors (7153393).

20904591 is a wasteful number, since it uses less digits than its factorization.

20904591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46301.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 20904591 is about 4572.1538688019. The cubic root of 20904591 is about 275.4739639187.

The spelling of 20904591 in words is "twenty million, nine hundred four thousand, five hundred ninety-one".