1808964865 has 4 divisors (see below), whose sum is σ = 2170757844. Its totient is φ = 1447171888.

The previous prime is 1808964853. The next prime is 1808964869. The reversal of 1808964865 is 5684698081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5684698081 = 47 ⋅120951023.

It can be written as a sum of positive squares in 2 ways, for example, as 1120374784 + 688590081 = 33472^2 + 26241^2 .

It is a cyclic number.

It is not a de Polignac number, because 1808964865 - 2¹¹ = 1808962817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1808964869) 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, 180896482 + ... + 180896491.

It is an arithmetic number, because the mean of its divisors is an integer number (542689461).

Almost surely, 2^1808964865 is an apocalyptic number.

It is an amenable number.

1808964865 is a deficient number, since it is larger than the sum of its proper divisors (361792979).

1808964865 is an equidigital number, since it uses as much as digits as its factorization.

1808964865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 361792978.

The product of its (nonzero) digits is 3317760, while the sum is 55.

The square root of 1808964865 is about 42531.9275956310. The cubic root of 1808964865 is about 1218.4565416088.

It can be divided in two parts, 180896 and 4865, that added together give a square (185761 = 431²).

The spelling of 1808964865 in words is "one billion, eight hundred eight million, nine hundred sixty-four thousand, eight hundred sixty-five".