66559987 has 8 divisors (see below), whose sum is σ = 71789760. Its totient is φ = 61345920.

The previous prime is 66559973. The next prime is 66559991. The reversal of 66559987 is 78995566.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 66559987 - 2¹⁹ = 66035699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66559937) 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, 5787 + ... + 12907.

It is an arithmetic number, because the mean of its divisors is an integer number (8973720).

Almost surely, 2^66559987 is an apocalyptic number.

66559987 is a deficient number, since it is larger than the sum of its proper divisors (5229773).

66559987 is a wasteful number, since it uses less digits than its factorization.

66559987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7853.

The product of its digits is 4082400, while the sum is 55.

The square root of 66559987 is about 8158.4304250266. The cubic root of 66559987 is about 405.2637351437.

The spelling of 66559987 in words is "sixty-six million, five hundred fifty-nine thousand, nine hundred eighty-seven".