66610909 has 4 divisors (see below), whose sum is σ = 68759680. Its totient is φ = 64462140.

The previous prime is 66610889. The next prime is 66610919. The reversal of 66610909 is 90901666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66610909 - 2¹³ = 66602717 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 (66610919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1074339 + ... + 1074400.

It is an arithmetic number, because the mean of its divisors is an integer number (17189920).

Almost surely, 2^66610909 is an apocalyptic number.

It is an amenable number.

66610909 is a deficient number, since it is larger than the sum of its proper divisors (2148771).

66610909 is a wasteful number, since it uses less digits than its factorization.

66610909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2148770.

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 66610909 is about 8161.5506492333. The cubic root of 66610909 is about 405.3670583780.

The spelling of 66610909 in words is "sixty-six million, six hundred ten thousand, nine hundred nine".