655521 has 8 divisors (see below), whose sum is σ = 877920. Its totient is φ = 435072.

The previous prime is 655517. The next prime is 655531. The reversal of 655521 is 125556.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 655521 - 2² = 655517 is a prime.

It is an Ulam number.

It is a Curzon number.

655521 is a lucky number.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 655491 and 655500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (655511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 750 + ... + 1368.

It is an arithmetic number, because the mean of its divisors is an integer number (109740).

2⁶⁵⁵⁵²¹ is an apocalyptic number.

It is an amenable number.

655521 is a deficient number, since it is larger than the sum of its proper divisors (222399).

655521 is a wasteful number, since it uses less digits than its factorization.

655521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 975.

The product of its digits is 1500, while the sum is 24.

The square root of 655521 is about 809.6425137059. The cubic root of 655521 is about 86.8684761245.

It can be divided in two parts, 655 and 521, that added together give a triangular number (1176 = T₄₈).

The spelling of 655521 in words is "six hundred fifty-five thousand, five hundred twenty-one".