655551 has 18 divisors (see below), whose sum is σ = 1027728. Its totient is φ = 402480.

The previous prime is 655547. The next prime is 655559. The reversal of 655551 is 155556.

655551 is a `hidden beast` number, since 655 + 5 + 5 + 1 = 666.

It is not a de Polignac number, because 655551 - 2² = 655547 is a prime.

It is a super-2 number, since 2×655551² = 859494227202, which contains 22 as substring.

It is a nialpdrome in base 10.

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 655551.

It is not an unprimeable number, because it can be changed into a prime (655559) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1306 + ... + 1736.

It is an arithmetic number, because the mean of its divisors is an integer number (57096).

2⁶⁵⁵⁵⁵¹ is an apocalyptic number.

655551 is a deficient number, since it is larger than the sum of its proper divisors (372177).

655551 is a wasteful number, since it uses less digits than its factorization.

655551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 463 (or 447 counting only the distinct ones).

The product of its digits is 3750, while the sum is 27.

The square root of 655551 is about 809.6610401890. The cubic root of 655551 is about 86.8698012865.

It can be divided in two parts, 65555 and 1, that added together give a palindrome (65556).

The spelling of 655551 in words is "six hundred fifty-five thousand, five hundred fifty-one".