66943613 has 6 divisors (see below), whose sum is σ = 73582782. Its totient is φ = 60857720.

The previous prime is 66943607. The next prime is 66943621. The reversal of 66943613 is 31634966.

It can be written as a sum of positive squares in only one way, i.e., 58951684 + 7991929 = 7678^2 + 2827^2 .

It is not a de Polignac number, because 66943613 - 2¹² = 66939517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66943313) 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, 276506 + ... + 276747.

It is an arithmetic number, because the mean of its divisors is an integer number (12263797).

Almost surely, 2^66943613 is an apocalyptic number.

It is an amenable number.

66943613 is a deficient number, since it is larger than the sum of its proper divisors (6639169).

66943613 is a wasteful number, since it uses less digits than its factorization.

66943613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553275 (or 553264 counting only the distinct ones).

The product of its digits is 69984, while the sum is 38.

The square root of 66943613 is about 8181.9076626420. The cubic root of 66943613 is about 406.0408385073.

The spelling of 66943613 in words is "sixty-six million, nine hundred forty-three thousand, six hundred thirteen".