505005661 has 4 divisors (see below), whose sum is σ = 505097824. Its totient is φ = 504913500.

The previous prime is 505005643. The next prime is 505005673. The reversal of 505005661 is 166500505.

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 a cyclic number.

It is not a de Polignac number, because 505005661 - 2⁵ = 505005629 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 (505005691) 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, 37305 + ... + 49006.

It is an arithmetic number, because the mean of its divisors is an integer number (126274456).

Almost surely, 2^505005661 is an apocalyptic number.

It is an amenable number.

505005661 is a deficient number, since it is larger than the sum of its proper divisors (92163).

505005661 is an equidigital number, since it uses as much as digits as its factorization.

505005661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92162.

The product of its (nonzero) digits is 4500, while the sum is 28.

The square root of 505005661 is about 22472.3310094881. The cubic root of 505005661 is about 796.3403997890.

The spelling of 505005661 in words is "five hundred five million, five thousand, six hundred sixty-one".