66391606 has 4 divisors (see below), whose sum is σ = 99587412. Its totient is φ = 33195802.

The previous prime is 66391601. The next prime is 66391627. The reversal of 66391606 is 60619366.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66391601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16597900 + ... + 16597903.

It is an arithmetic number, because the mean of its divisors is an integer number (24896853).

Almost surely, 2^66391606 is an apocalyptic number.

66391606 is a deficient number, since it is larger than the sum of its proper divisors (33195806).

66391606 is a wasteful number, since it uses less digits than its factorization.

66391606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33195805.

The product of its (nonzero) digits is 34992, while the sum is 37.

The square root of 66391606 is about 8148.1044421387. The cubic root of 66391606 is about 404.9217061477.

The spelling of 66391606 in words is "sixty-six million, three hundred ninety-one thousand, six hundred six".