20659309 has 4 divisors (see below), whose sum is σ = 22537440. Its totient is φ = 18781180.

The previous prime is 20659291. The next prime is 20659319. The reversal of 20659309 is 90395602.

It is a happy number.

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.

It is not a de Polignac number, because 20659309 - 2⁵ = 20659277 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 (20659319) 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, 939049 + ... + 939070.

It is an arithmetic number, because the mean of its divisors is an integer number (5634360).

Almost surely, 2^20659309 is an apocalyptic number.

It is an amenable number.

20659309 is a deficient number, since it is larger than the sum of its proper divisors (1878131).

20659309 is a wasteful number, since it uses less digits than its factorization.

20659309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1878130.

The product of its (nonzero) digits is 14580, while the sum is 34.

The square root of 20659309 is about 4545.2512581814. The cubic root of 20659309 is about 274.3923065967.

The spelling of 20659309 in words is "twenty million, six hundred fifty-nine thousand, three hundred nine".