66231665 has 16 divisors (see below), whose sum is σ = 82978320. Its totient is φ = 50699520.

The previous prime is 66231647. The next prime is 66231713. The reversal of 66231665 is 56613266.

It can be written as a sum of positive squares in 8 ways, for example, as 9138529 + 57093136 = 3023^2 + 7556^2 .

It is not a de Polignac number, because 66231665 - 2¹² = 66227569 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8351 + ... + 14219.

It is an arithmetic number, because the mean of its divisors is an integer number (5186145).

Almost surely, 2^66231665 is an apocalyptic number.

It is an amenable number.

66231665 is a deficient number, since it is larger than the sum of its proper divisors (16746655).

66231665 is a wasteful number, since it uses less digits than its factorization.

66231665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5972.

The product of its digits is 38880, while the sum is 35.

The square root of 66231665 is about 8138.2839100144. The cubic root of 66231665 is about 404.5962851969.

The spelling of 66231665 in words is "sixty-six million, two hundred thirty-one thousand, six hundred sixty-five".