655891 has 4 divisors (see below), whose sum is σ = 684432. Its totient is φ = 627352.

The previous prime is 655883. The next prime is 655901. The reversal of 655891 is 198556.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 655891 - 2³ = 655883 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 655891.

It is not an unprimeable number, because it can be changed into a prime (656891) 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, 14236 + ... + 14281.

It is an arithmetic number, because the mean of its divisors is an integer number (171108).

2⁶⁵⁵⁸⁹¹ is an apocalyptic number.

655891 is a deficient number, since it is larger than the sum of its proper divisors (28541).

655891 is a wasteful number, since it uses less digits than its factorization.

655891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28540.

The product of its digits is 10800, while the sum is 34.

The square root of 655891 is about 809.8709773785. The cubic root of 655891 is about 86.8848169642.

It can be divided in two parts, 6558 and 91, that multiplied together give a triangular number (596778 = T₁₀₉₂).

The spelling of 655891 in words is "six hundred fifty-five thousand, eight hundred ninety-one".