20259509 has 4 divisors (see below), whose sum is σ = 20311980. Its totient is φ = 20207040.

The previous prime is 20259497. The next prime is 20259521. The reversal of 20259509 is 90595202.

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

It is an interprime number because it is at equal distance from previous prime (20259497) and next prime (20259521).

It can be written as a sum of positive squares in 2 ways, for example, as 3161284 + 17098225 = 1778^2 + 4135^2 .

It is a cyclic number.

It is not a de Polignac number, because 20259509 - 2¹² = 20255413 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20259539) 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, 25652 + ... + 26429.

It is an arithmetic number, because the mean of its divisors is an integer number (5077995).

Almost surely, 2^20259509 is an apocalyptic number.

It is an amenable number.

20259509 is a deficient number, since it is larger than the sum of its proper divisors (52471).

20259509 is an equidigital number, since it uses as much as digits as its factorization.

20259509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52470.

The product of its (nonzero) digits is 8100, while the sum is 32.

The square root of 20259509 is about 4501.0564315503. The cubic root of 20259509 is about 272.6107464453.

The spelling of 20259509 in words is "twenty million, two hundred fifty-nine thousand, five hundred nine".