1861665829 has 2 divisors, whose sum is σ = 1861665830. Its totient is φ = 1861665828.

The previous prime is 1861665823. The next prime is 1861665857. The reversal of 1861665829 is 9285661681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1855024900 + 6640929 = 43070^2 + 2577^2 .

It is a cyclic number.

It is not a de Polignac number, because 1861665829 - 2⁵ = 1861665797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1861665823) 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 as a sum of consecutive naturals, namely, 930832914 + 930832915.

It is an arithmetic number, because the mean of its divisors is an integer number (930832915).

Almost surely, 2^1861665829 is an apocalyptic number.

It is an amenable number.

1861665829 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861665829 is an equidigital number, since it uses as much as digits as its factorization.

1861665829 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1244160, while the sum is 52.

The square root of 1861665829 is about 43147.0257259988. The cubic root of 1861665829 is about 1230.1759787430.

The spelling of 1861665829 in words is "one billion, eight hundred sixty-one million, six hundred sixty-five thousand, eight hundred twenty-nine".