66665331 has 12 divisors (see below), whose sum is σ = 96365152. Its totient is φ = 44410896.

The previous prime is 66665329. The next prime is 66665341. The reversal of 66665331 is 13356666.

It is a happy number.

It is not a de Polignac number, because 66665331 - 2¹ = 66665329 is a prime.

It is a super-2 number, since 2×66665331² = 8888532714679122, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66665311) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22710 + ... + 25476.

Almost surely, 2^66665331 is an apocalyptic number.

66665331 is a deficient number, since it is larger than the sum of its proper divisors (29699821).

66665331 is a wasteful number, since it uses less digits than its factorization.

66665331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5450 (or 5447 counting only the distinct ones).

The product of its digits is 58320, while the sum is 36.

The square root of 66665331 is about 8164.8840163226. The cubic root of 66665331 is about 405.4774250887.

The spelling of 66665331 in words is "sixty-six million, six hundred sixty-five thousand, three hundred thirty-one".