66681205 has 4 divisors (see below), whose sum is σ = 80017452. Its totient is φ = 53344960.

The previous prime is 66681169. The next prime is 66681229. The reversal of 66681205 is 50218666.

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

It can be written as a sum of positive squares in 2 ways, for example, as 41460721 + 25220484 = 6439^2 + 5022^2 .

It is not a de Polignac number, because 66681205 - 2⁹ = 66680693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6668116 + ... + 6668125.

It is an arithmetic number, because the mean of its divisors is an integer number (20004363).

Almost surely, 2^66681205 is an apocalyptic number.

It is an amenable number.

66681205 is a deficient number, since it is larger than the sum of its proper divisors (13336247).

66681205 is a wasteful number, since it uses less digits than its factorization.

66681205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13336246.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 66681205 is about 8165.8560482046. The cubic root of 66681205 is about 405.5096059226.

The spelling of 66681205 in words is "sixty-six million, six hundred eighty-one thousand, two hundred five".