66865563 has 12 divisors (see below), whose sum is σ = 97119568. Its totient is φ = 44329680.

The previous prime is 66865553. The next prime is 66865583. The reversal of 66865563 is 36556866.

66865563 is a `hidden beast` number, since 6 + 6 + 86 + 5 + 563 = 666.

It is not a de Polignac number, because 66865563 - 2⁶ = 66865499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66865553) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18895 + ... + 22152.

Almost surely, 2^66865563 is an apocalyptic number.

66865563 is a deficient number, since it is larger than the sum of its proper divisors (30254005).

66865563 is a wasteful number, since it uses less digits than its factorization.

66865563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41234 (or 41231 counting only the distinct ones).

The product of its digits is 777600, while the sum is 45.

The square root of 66865563 is about 8177.1366015250. The cubic root of 66865563 is about 405.8829752428.

The spelling of 66865563 in words is "sixty-six million, eight hundred sixty-five thousand, five hundred sixty-three".