66673913 has 4 divisors (see below), whose sum is σ = 68300148. Its totient is φ = 65047680.

The previous prime is 66673903. The next prime is 66673921. The reversal of 66673913 is 31937666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31937666 = 2 ⋅15968833.

It can be written as a sum of positive squares in 2 ways, for example, as 5396329 + 61277584 = 2323^2 + 7828^2 .

It is a cyclic number.

It is not a de Polignac number, because 66673913 - 2⁸ = 66673657 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41), and also a Moran number because the ratio is a prime number: 1626193 = 66673913 / (6 + 6 + 6 + 7 + 3 + 9 + 1 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66673903) 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, 813056 + ... + 813137.

It is an arithmetic number, because the mean of its divisors is an integer number (17075037).

Almost surely, 2^66673913 is an apocalyptic number.

It is an amenable number.

66673913 is a deficient number, since it is larger than the sum of its proper divisors (1626235).

66673913 is a wasteful number, since it uses less digits than its factorization.

66673913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1626234.

The product of its digits is 122472, while the sum is 41.

The square root of 66673913 is about 8165.4095426990. The cubic root of 66673913 is about 405.4948237270.

The spelling of 66673913 in words is "sixty-six million, six hundred seventy-three thousand, nine hundred thirteen".