855521 has 2 divisors, whose sum is σ = 855522. Its totient is φ = 855520.

The previous prime is 855511. The next prime is 855527. The reversal of 855521 is 125558.

855521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 829921 + 25600 = 911^2 + 160^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-855521 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (855527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 427760 + 427761.

It is an arithmetic number, because the mean of its divisors is an integer number (427761).

2⁸⁵⁵⁵²¹ is an apocalyptic number.

It is an amenable number.

855521 is a deficient number, since it is larger than the sum of its proper divisors (1).

855521 is an equidigital number, since it uses as much as digits as its factorization.

855521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2000, while the sum is 26.

The square root of 855521 is about 924.9437820754. The cubic root of 855521 is about 94.9314741282.

The spelling of 855521 in words is "eight hundred fifty-five thousand, five hundred twenty-one".