505661 has 8 divisors (see below), whose sum is σ = 551544. Its totient is φ = 460800.

The previous prime is 505657. The next prime is 505663. The reversal of 505661 is 166505.

It can be written as a sum of positive squares in 4 ways, for example, as 122500 + 383161 = 350^2 + 619^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 505661 - 2² = 505657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (505663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1061 + ... + 1461.

It is an arithmetic number, because the mean of its divisors is an integer number (68943).

2⁵⁰⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

505661 is a deficient number, since it is larger than the sum of its proper divisors (45883).

505661 is a wasteful number, since it uses less digits than its factorization.

505661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 505661 is about 711.0984460678. The cubic root of 505661 is about 79.6684717607.

The spelling of 505661 in words is "five hundred five thousand, six hundred sixty-one".