20808513601 has 4 divisors (see below), whose sum is σ = 20817817812. Its totient is φ = 20799209392.

The previous prime is 20808513577. The next prime is 20808513617. The reversal of 20808513601 is 10631580802.

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 16449345025 + 4359168576 = 128255^2 + 66024^2 .

It is a cyclic number.

It is not a de Polignac number, because 20808513601 - 2¹³ = 20808505409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20808513641) 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, 4648750 + ... + 4653223.

It is an arithmetic number, because the mean of its divisors is an integer number (5204454453).

Almost surely, 2^20808513601 is an apocalyptic number.

It is an amenable number.

20808513601 is a deficient number, since it is larger than the sum of its proper divisors (9304211).

20808513601 is an equidigital number, since it uses as much as digits as its factorization.

20808513601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9304210.

The product of its (nonzero) digits is 11520, while the sum is 34.

The spelling of 20808513601 in words is "twenty billion, eight hundred eight million, five hundred thirteen thousand, six hundred one".