20810685065 has 24 divisors (see below), whose sum is σ = 26718244632. Its totient is φ = 15507087360.

The previous prime is 20810685061. The next prime is 20810685067. The reversal of 20810685065 is 56058601802.

It can be written as a sum of positive squares in 12 ways, for example, as 27426169 + 20783258896 = 5237^2 + 144164^2 .

It is not a de Polignac number, because 20810685065 - 2² = 20810685061 is a prime.

It is a super-2 number, since 2×20810685065² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20810685061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 786755 + ... + 812775.

It is an arithmetic number, because the mean of its divisors is an integer number (1113260193).

Almost surely, 2^20810685065 is an apocalyptic number.

It is an amenable number.

20810685065 is a deficient number, since it is larger than the sum of its proper divisors (5907559567).

20810685065 is an equidigital number, since it uses as much as digits as its factorization.

20810685065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26237 (or 26140 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 41.

The spelling of 20810685065 in words is "twenty billion, eight hundred ten million, six hundred eighty-five thousand, sixty-five".