66391090 has 8 divisors (see below), whose sum is σ = 119503980. Its totient is φ = 26556432.

The previous prime is 66391079. The next prime is 66391109. The reversal of 66391090 is 9019366.

66391090 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 65755881 + 635209 = 8109^2 + 797^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3319545 + ... + 3319564.

Almost surely, 2^66391090 is an apocalyptic number.

66391090 is a deficient number, since it is larger than the sum of its proper divisors (53112890).

66391090 is a wasteful number, since it uses less digits than its factorization.

66391090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6639116.

The product of its (nonzero) digits is 8748, while the sum is 34.

The square root of 66391090 is about 8148.0727782709. The cubic root of 66391090 is about 404.9206571188.

The spelling of 66391090 in words is "sixty-six million, three hundred ninety-one thousand, ninety".