66563391 has 8 divisors (see below), whose sum is σ = 88986880. Its totient is φ = 44257752.

The previous prime is 66563369. The next prime is 66563401. The reversal of 66563391 is 19336566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66563391 - 2⁵ = 66563359 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 (66563351) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28135 + ... + 30408.

It is an arithmetic number, because the mean of its divisors is an integer number (11123360).

Almost surely, 2^66563391 is an apocalyptic number.

66563391 is a deficient number, since it is larger than the sum of its proper divisors (22423489).

66563391 is a wasteful number, since it uses less digits than its factorization.

66563391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58925.

The product of its digits is 87480, while the sum is 39.

The square root of 66563391 is about 8158.6390409185. The cubic root of 66563391 is about 405.2706436699.

The spelling of 66563391 in words is "sixty-six million, five hundred sixty-three thousand, three hundred ninety-one".