1881612857 has 4 divisors (see below), whose sum is σ = 1881700596. Its totient is φ = 1881525120.

The previous prime is 1881612841. The next prime is 1881612923. The reversal of 1881612857 is 7582161881.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 7582161881 = 7 ⋅1083165983.

It can be written as a sum of positive squares in 2 ways, for example, as 1118969401 + 762643456 = 33451^2 + 27616^2 .

It is a cyclic number.

It is not a de Polignac number, because 1881612857 - 2⁴ = 1881612841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1881618857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12113 + ... + 62529.

It is an arithmetic number, because the mean of its divisors is an integer number (470425149).

Almost surely, 2^1881612857 is an apocalyptic number.

It is an amenable number.

1881612857 is a deficient number, since it is larger than the sum of its proper divisors (87739).

1881612857 is an equidigital number, since it uses as much as digits as its factorization.

1881612857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87738.

The product of its digits is 215040, while the sum is 47.

The square root of 1881612857 is about 43377.5616765166. The cubic root of 1881612857 is about 1234.5539991591.

The spelling of 1881612857 in words is "one billion, eight hundred eighty-one million, six hundred twelve thousand, eight hundred fifty-seven".