66403313 has 4 divisors (see below), whose sum is σ = 68022948. Its totient is φ = 64783680.

The previous prime is 66403297. The next prime is 66403321. The reversal of 66403313 is 31330466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31330466 = 2 ⋅15665233.

It can be written as a sum of positive squares in 2 ways, for example, as 2211169 + 64192144 = 1487^2 + 8012^2 .

It is a cyclic number.

It is not a de Polignac number, because 66403313 - 2⁴ = 66403297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66403373) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 809756 + ... + 809837.

It is an arithmetic number, because the mean of its divisors is an integer number (17005737).

Almost surely, 2^66403313 is an apocalyptic number.

It is an amenable number.

66403313 is a deficient number, since it is larger than the sum of its proper divisors (1619635).

66403313 is a wasteful number, since it uses less digits than its factorization.

66403313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1619634.

The product of its (nonzero) digits is 3888, while the sum is 26.

The square root of 66403313 is about 8148.8227984170. The cubic root of 66403313 is about 404.9455050388.

Adding to 66403313 its reverse (31330466), we get a palindrome (97733779).

The spelling of 66403313 in words is "sixty-six million, four hundred three thousand, three hundred thirteen".