655581 has 4 divisors (see below), whose sum is σ = 874112. Its totient is φ = 437052.

The previous prime is 655579. The next prime is 655583. The reversal of 655581 is 185556.

It is a happy number.

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 an interprime number because it is at equal distance from previous prime (655579) and next prime (655583).

It is not a de Polignac number, because 655581 - 2¹ = 655579 is a prime.

It is a super-2 number, since 2×655581² = 859572895122, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 655581.

It is not an unprimeable number, because it can be changed into a prime (655583) 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, 109261 + ... + 109266.

It is an arithmetic number, because the mean of its divisors is an integer number (218528).

2⁶⁵⁵⁵⁸¹ is an apocalyptic number.

It is an amenable number.

655581 is a deficient number, since it is larger than the sum of its proper divisors (218531).

655581 is a wasteful number, since it uses less digits than its factorization.

655581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218530.

The product of its digits is 6000, while the sum is 30.

The square root of 655581 is about 809.6795662483. The cubic root of 655581 is about 86.8711264080.

The spelling of 655581 in words is "six hundred fifty-five thousand, five hundred eighty-one".