1861125865 has 4 divisors (see below), whose sum is σ = 2233351044. Its totient is φ = 1488900688.

The previous prime is 1861125859. The next prime is 1861125907. The reversal of 1861125865 is 5685211681.

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 235100889 + 1626024976 = 15333^2 + 40324^2 .

It is a cyclic number.

It is not a de Polignac number, because 1861125865 - 2⁷ = 1861125737 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 186112582 + ... + 186112591.

It is an arithmetic number, because the mean of its divisors is an integer number (558337761).

Almost surely, 2^1861125865 is an apocalyptic number.

It is an amenable number.

1861125865 is a deficient number, since it is larger than the sum of its proper divisors (372225179).

1861125865 is an equidigital number, since it uses as much as digits as its factorization.

1861125865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372225178.

The product of its digits is 115200, while the sum is 43.

The square root of 1861125865 is about 43140.7680158803. The cubic root of 1861125865 is about 1230.0570324096.

The spelling of 1861125865 in words is "one billion, eight hundred sixty-one million, one hundred twenty-five thousand, eight hundred sixty-five".