855981 has 24 divisors (see below), whose sum is σ = 1477440. Its totient is φ = 488376.

The previous prime is 855947. The next prime is 855983. The reversal of 855981 is 189558.

It is not a de Polignac number, because 855981 - 2¹⁰ = 854957 is a prime.

It is a super-2 number, since 2×855981² = 1465406944722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (855983) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1000 + ... + 1646.

It is an arithmetic number, because the mean of its divisors is an integer number (61560).

2⁸⁵⁵⁹⁸¹ is an apocalyptic number.

It is an amenable number.

855981 is a deficient number, since it is larger than the sum of its proper divisors (621459).

855981 is a wasteful number, since it uses less digits than its factorization.

855981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 670 (or 657 counting only the distinct ones).

The product of its digits is 14400, while the sum is 36.

The square root of 855981 is about 925.1924124202. The cubic root of 855981 is about 94.9484854596.

The spelling of 855981 in words is "eight hundred fifty-five thousand, nine hundred eighty-one".