66591986 has 8 divisors (see below), whose sum is σ = 100140780. Its totient is φ = 33211728.

The previous prime is 66591983. The next prime is 66591991. The reversal of 66591986 is 68919566.

It can be written as a sum of positive squares in 2 ways, for example, as 65529025 + 1062961 = 8095^2 + 1031^2 .

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

It is not an unprimeable number, because it can be changed into a prime (66591983) 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, 41141 + ... + 42728.

Almost surely, 2^66591986 is an apocalyptic number.

66591986 is a deficient number, since it is larger than the sum of its proper divisors (33548794).

66591986 is a wasteful number, since it uses less digits than its factorization.

66591986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84268.

The product of its digits is 699840, while the sum is 50.

The square root of 66591986 is about 8160.3912896380. The cubic root of 66591986 is about 405.3286688336.

The spelling of 66591986 in words is "sixty-six million, five hundred ninety-one thousand, nine hundred eighty-six".