20570509 has 4 divisors (see below), whose sum is σ = 20678400. Its totient is φ = 20462620.

The previous prime is 20570497. The next prime is 20570549. The reversal of 20570509 is 90507502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90507502 = 2 ⋅45253751.

It is a cyclic number.

It is not a de Polignac number, because 20570509 - 2⁵ = 20570477 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 (20570549) 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 3 ways as a sum of consecutive naturals, for example, 53659 + ... + 54040.

It is an arithmetic number, because the mean of its divisors is an integer number (5169600).

Almost surely, 2^20570509 is an apocalyptic number.

It is an amenable number.

20570509 is a deficient number, since it is larger than the sum of its proper divisors (107891).

20570509 is a wasteful number, since it uses less digits than its factorization.

20570509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107890.

The product of its (nonzero) digits is 3150, while the sum is 28.

The square root of 20570509 is about 4535.4723017565. The cubic root of 20570509 is about 273.9986014101.

The spelling of 20570509 in words is "twenty million, five hundred seventy thousand, five hundred nine".