66716613 has 6 divisors (see below), whose sum is σ = 96368454. Its totient is φ = 44477736.

The previous prime is 66716609. The next prime is 66716621. The reversal of 66716613 is 31661766.

It can be written as a sum of positive squares in only one way, i.e., 51365889 + 15350724 = 7167^2 + 3918^2 .

It is not a de Polignac number, because 66716613 - 2² = 66716609 is a prime.

It is a super-2 number, since 2×66716613² = 8902212900383538, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66716603) 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, 3706470 + ... + 3706487.

It is an arithmetic number, because the mean of its divisors is an integer number (16061409).

Almost surely, 2^66716613 is an apocalyptic number.

It is an amenable number.

66716613 is a deficient number, since it is larger than the sum of its proper divisors (29651841).

66716613 is a wasteful number, since it uses less digits than its factorization.

66716613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7412963 (or 7412960 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 66716613 is about 8168.0238124041. The cubic root of 66716613 is about 405.5813689900.

The spelling of 66716613 in words is "sixty-six million, seven hundred sixteen thousand, six hundred thirteen".