1089685865 has 4 divisors (see below), whose sum is σ = 1307623044. Its totient is φ = 871748688.

The previous prime is 1089685859. The next prime is 1089685879. The reversal of 1089685865 is 5685869801.

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 491198569 + 598487296 = 22163^2 + 24464^2 .

It is a cyclic number.

It is not a de Polignac number, because 1089685865 - 2⁸ = 1089685609 is a prime.

It is a super-3 number, since 3×1089685865³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1089685865.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108968582 + ... + 108968591.

It is an arithmetic number, because the mean of its divisors is an integer number (326905761).

Almost surely, 2^1089685865 is an apocalyptic number.

It is an amenable number.

1089685865 is a deficient number, since it is larger than the sum of its proper divisors (217937179).

1089685865 is an equidigital number, since it uses as much as digits as its factorization.

1089685865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217937178.

The product of its (nonzero) digits is 4147200, while the sum is 56.

The square root of 1089685865 is about 33010.3902582202. The cubic root of 1089685865 is about 1029.0435917303.

The spelling of 1089685865 in words is "one billion, eighty-nine million, six hundred eighty-five thousand, eight hundred sixty-five".