66351321 has 6 divisors (see below), whose sum is σ = 95840810. Its totient is φ = 44234208.

The previous prime is 66351319. The next prime is 66351353. The reversal of 66351321 is 12315366.

66351321 is a `hidden beast` number, since 6 + 635 + 1 + 3 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 65610000 + 741321 = 8100^2 + 861^2 .

It is not a de Polignac number, because 66351321 - 2¹ = 66351319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66351301) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3686176 + ... + 3686193.

Almost surely, 2^66351321 is an apocalyptic number.

It is an amenable number.

66351321 is a deficient number, since it is larger than the sum of its proper divisors (29489489).

66351321 is a wasteful number, since it uses less digits than its factorization.

66351321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7372375 (or 7372372 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 66351321 is about 8145.6320196778. The cubic root of 66351321 is about 404.8397903135.

Adding to 66351321 its reverse (12315366), we get a palindrome (78666687).

It can be divided in two parts, 663 and 51321, that added together give a square (51984 = 228²).

The spelling of 66351321 in words is "sixty-six million, three hundred fifty-one thousand, three hundred twenty-one".