20617872805 has 8 divisors (see below), whose sum is σ = 24744353400. Its totient is φ = 16492360896.

The previous prime is 20617872797. The next prime is 20617872809. The reversal of 20617872805 is 50827871602.

It can be written as a sum of positive squares in 4 ways, for example, as 3240569476 + 17377303329 = 56926^2 + 131823^2 .

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 20617872805 - 2³ = 20617872797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20617872809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194490 + ... + 281179.

It is an arithmetic number, because the mean of its divisors is an integer number (3093044175).

Almost surely, 2^20617872805 is an apocalyptic number.

It is an amenable number.

20617872805 is a deficient number, since it is larger than the sum of its proper divisors (4126480595).

20617872805 is an equidigital number, since it uses as much as digits as its factorization.

20617872805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484343.

The product of its (nonzero) digits is 376320, while the sum is 46.

The spelling of 20617872805 in words is "twenty billion, six hundred seventeen million, eight hundred seventy-two thousand, eight hundred five".