855881861 has 2 divisors, whose sum is σ = 855881862. Its totient is φ = 855881860.

The previous prime is 855881837. The next prime is 855881869. The reversal of 855881861 is 168188558.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 520296100 + 335585761 = 22810^2 + 18319^2 .

It is a cyclic number.

It is not a de Polignac number, because 855881861 - 2¹⁸ = 855619717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (855881869) 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 as a sum of consecutive naturals, namely, 427940930 + 427940931.

It is an arithmetic number, because the mean of its divisors is an integer number (427940931).

Almost surely, 2^855881861 is an apocalyptic number.

It is an amenable number.

855881861 is a deficient number, since it is larger than the sum of its proper divisors (1).

855881861 is an equidigital number, since it uses as much as digits as its factorization.

855881861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 614400, while the sum is 50.

The square root of 855881861 is about 29255.4586530446. The cubic root of 855881861 is about 949.4481970014.

The spelling of 855881861 in words is "eight hundred fifty-five million, eight hundred eighty-one thousand, eight hundred sixty-one".