66843813 has 16 divisors (see below), whose sum is σ = 94870656. Its totient is φ = 41717760.

The previous prime is 66843809. The next prime is 66843839. The reversal of 66843813 is 31834866.

It is not a de Polignac number, because 66843813 - 2² = 66843809 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66843883) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6448 + ... + 13238.

It is an arithmetic number, because the mean of its divisors is an integer number (5929416).

Almost surely, 2^66843813 is an apocalyptic number.

It is an amenable number.

66843813 is a deficient number, since it is larger than the sum of its proper divisors (28026843).

66843813 is a wasteful number, since it uses less digits than its factorization.

66843813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7004.

The product of its digits is 82944, while the sum is 39.

The square root of 66843813 is about 8175.8065657157. The cubic root of 66843813 is about 405.8389619935.

The spelling of 66843813 in words is "sixty-six million, eight hundred forty-three thousand, eight hundred thirteen".