20508559409 has 8 divisors (see below), whose sum is σ = 22145358312. Its totient is φ = 18880220160.

The previous prime is 20508559349. The next prime is 20508559417. The reversal of 20508559409 is 90495580502.

It can be written as a sum of positive squares in 4 ways, for example, as 2776973809 + 17731585600 = 52697^2 + 133160^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20508559409 - 2³² = 16213592113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20508559439) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2109872 + ... + 2119569.

It is an arithmetic number, because the mean of its divisors is an integer number (2768169789).

Almost surely, 2^20508559409 is an apocalyptic number.

It is an amenable number.

20508559409 is a deficient number, since it is larger than the sum of its proper divisors (1636798903).

20508559409 is a wasteful number, since it uses less digits than its factorization.

20508559409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4229827.

The product of its (nonzero) digits is 648000, while the sum is 47.

The spelling of 20508559409 in words is "twenty billion, five hundred eight million, five hundred fifty-nine thousand, four hundred nine".