505981566 has 80 divisors (see below), whose sum is σ = 1193056128. Its totient is φ = 160056000.

The previous prime is 505981561. The next prime is 505981583. The reversal of 505981566 is 665189505.

It is a happy number.

505981566 is a `hidden beast` number, since 5 + 0 + 5 + 9 + 81 + 566 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (505981561) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 265216 + ... + 267116.

Almost surely, 2^505981566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 505981566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (596528064).

505981566 is an abundant number, since it is smaller than the sum of its proper divisors (687074562).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

505981566 is a wasteful number, since it uses less digits than its factorization.

505981566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1999 (or 1990 counting only the distinct ones).

The product of its (nonzero) digits is 324000, while the sum is 45.

The square root of 505981566 is about 22494.0340090434. The cubic root of 505981566 is about 796.8530359621.

The spelling of 505981566 in words is "five hundred five million, nine hundred eighty-one thousand, five hundred sixty-six".