1851981843 has 16 divisors (see below), whose sum is σ = 2523502080. Its totient is φ = 1207592736.

The previous prime is 1851981841. The next prime is 1851981863. The reversal of 1851981843 is 3481891581.

It is a happy number.

It is not a de Polignac number, because 1851981843 - 2¹ = 1851981841 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1851981792 and 1851981801.

It is not an unprimeable number, because it can be changed into a prime (1851981841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 275721 + ... + 282357.

It is an arithmetic number, because the mean of its divisors is an integer number (157718880).

Almost surely, 2^1851981843 is an apocalyptic number.

1851981843 is a deficient number, since it is larger than the sum of its proper divisors (671520237).

1851981843 is a wasteful number, since it uses less digits than its factorization.

1851981843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8666.

The product of its digits is 276480, while the sum is 48.

The square root of 1851981843 is about 43034.6586253452. The cubic root of 1851981843 is about 1228.0392323636.

The spelling of 1851981843 in words is "one billion, eight hundred fifty-one million, nine hundred eighty-one thousand, eight hundred forty-three".