66351665 has 16 divisors (see below), whose sum is σ = 83655936. Its totient is φ = 50424000.

The previous prime is 66351569. The next prime is 66351683. The reversal of 66351665 is 56615366.

It is not a de Polignac number, because 66351665 - 2⁸ = 66351409 is a prime.

It is a Duffinian number.

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, 15455 + ... + 19275.

It is an arithmetic number, because the mean of its divisors is an integer number (5228496).

Almost surely, 2^66351665 is an apocalyptic number.

It is an amenable number.

66351665 is a deficient number, since it is larger than the sum of its proper divisors (17304271).

66351665 is a wasteful number, since it uses less digits than its factorization.

66351665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4000.

The product of its digits is 97200, while the sum is 38.

The square root of 66351665 is about 8145.6531352618. The cubic root of 66351665 is about 404.8404899462.

The spelling of 66351665 in words is "sixty-six million, three hundred fifty-one thousand, six hundred sixty-five".