513661 has 4 divisors (see below), whose sum is σ = 518752. Its totient is φ = 508572.

The previous prime is 513649. The next prime is 513673. The reversal of 513661 is 166315.

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 (513649) and next prime (513673).

It is a cyclic number.

It is not a de Polignac number, because 513661 - 2⁷ = 513533 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 (513631) 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, 2391 + ... + 2596.

It is an arithmetic number, because the mean of its divisors is an integer number (129688).

2⁵¹³⁶⁶¹ is an apocalyptic number.

It is an amenable number.

513661 is a deficient number, since it is larger than the sum of its proper divisors (5091).

513661 is a wasteful number, since it uses less digits than its factorization.

513661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5090.

The product of its digits is 540, while the sum is 22.

The square root of 513661 is about 716.7014720230. The cubic root of 513661 is about 80.0864170343.

Adding to 513661 its reverse (166315), we get a palindrome (679976).

The spelling of 513661 in words is "five hundred thirteen thousand, six hundred sixty-one".