855021 has 4 divisors (see below), whose sum is σ = 1140032. Its totient is φ = 570012.

The previous prime is 854999. The next prime is 855031. The reversal of 855021 is 120558.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 855021 - 2⁶ = 854957 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (855031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142501 + ... + 142506.

It is an arithmetic number, because the mean of its divisors is an integer number (285008).

2⁸⁵⁵⁰²¹ is an apocalyptic number.

It is an amenable number.

855021 is a deficient number, since it is larger than the sum of its proper divisors (285011).

855021 is a wasteful number, since it uses less digits than its factorization.

855021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285010.

The product of its (nonzero) digits is 400, while the sum is 21.

The square root of 855021 is about 924.6734558751. The cubic root of 855021 is about 94.9129766329.

Adding to 855021 its reverse (120558), we get a palindrome (975579).

The spelling of 855021 in words is "eight hundred fifty-five thousand, twenty-one".