505542509 has 4 divisors (see below), whose sum is σ = 505587804. Its totient is φ = 505497216.

The previous prime is 505542497. The next prime is 505542523. The reversal of 505542509 is 905245505.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 905245505 = 5 ⋅181049101.

It can be written as a sum of positive squares in 2 ways, for example, as 124434025 + 381108484 = 11155^2 + 19522^2 .

It is a cyclic number.

It is not a de Polignac number, because 505542509 - 2¹⁶ = 505476973 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 (505542559) 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, 7259 + ... + 32615.

It is an arithmetic number, because the mean of its divisors is an integer number (126396951).

Almost surely, 2^505542509 is an apocalyptic number.

It is an amenable number.

505542509 is a deficient number, since it is larger than the sum of its proper divisors (45295).

505542509 is a wasteful number, since it uses less digits than its factorization.

505542509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45294.

The product of its (nonzero) digits is 45000, while the sum is 35.

The square root of 505542509 is about 22484.2724810032. The cubic root of 505542509 is about 796.6224839869.

The spelling of 505542509 in words is "five hundred five million, five hundred forty-two thousand, five hundred nine".