20578109 has 4 divisors (see below), whose sum is σ = 21788604. Its totient is φ = 19367616.

The previous prime is 20578097. The next prime is 20578127. The reversal of 20578109 is 90187502.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13032100 + 7546009 = 3610^2 + 2747^2 .

It is a cyclic number.

It is not a de Polignac number, because 20578109 - 2⁴ = 20578093 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 (20578199) 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, 605222 + ... + 605255.

It is an arithmetic number, because the mean of its divisors is an integer number (5447151).

Almost surely, 2^20578109 is an apocalyptic number.

It is an amenable number.

20578109 is a deficient number, since it is larger than the sum of its proper divisors (1210495).

20578109 is a wasteful number, since it uses less digits than its factorization.

20578109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1210494.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 20578109 is about 4536.3100643585. The cubic root of 20578109 is about 274.0323411840.

The spelling of 20578109 in words is "twenty million, five hundred seventy-eight thousand, one hundred nine".