1205655845 has 4 divisors (see below), whose sum is σ = 1446787020. Its totient is φ = 964524672.

The previous prime is 1205655779. The next prime is 1205655851. The reversal of 1205655845 is 5485565021.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5485565021 = 23 ⋅238502827.

It can be written as a sum of positive squares in 2 ways, for example, as 187854436 + 1017801409 = 13706^2 + 31903^2 .

It is a cyclic number.

It is not a de Polignac number, because 1205655845 - 2¹⁸ = 1205393701 is a prime.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 120565580 + ... + 120565589.

It is an arithmetic number, because the mean of its divisors is an integer number (361696755).

Almost surely, 2^1205655845 is an apocalyptic number.

It is an amenable number.

1205655845 is a deficient number, since it is larger than the sum of its proper divisors (241131175).

1205655845 is an equidigital number, since it uses as much as digits as its factorization.

1205655845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241131174.

The product of its (nonzero) digits is 240000, while the sum is 41.

The square root of 1205655845 is about 34722.5552775138. Note that the first 3 decimals coincide. The cubic root of 1205655845 is about 1064.3254620489.

The spelling of 1205655845 in words is "one billion, two hundred five million, six hundred fifty-five thousand, eight hundred forty-five".