66378013 has 16 divisors (see below), whose sum is σ = 78306480. Its totient is φ = 55673856.

The previous prime is 66377999. The next prime is 66378029. The reversal of 66378013 is 31087366.

It can be written as a sum of positive squares in 8 ways, for example, as 85849 + 66292164 = 293^2 + 8142^2 .

It is a cyclic number.

It is not a de Polignac number, because 66378013 - 2⁵ = 66377981 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66378013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66378043) 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, 1231 + ... + 11587.

It is an arithmetic number, because the mean of its divisors is an integer number (4894155).

Almost surely, 2^66378013 is an apocalyptic number.

It is an amenable number.

66378013 is a deficient number, since it is larger than the sum of its proper divisors (11928467).

66378013 is a wasteful number, since it uses less digits than its factorization.

66378013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10416.

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 66378013 is about 8147.2702790567. The cubic root of 66378013 is about 404.8940697402.

The spelling of 66378013 in words is "sixty-six million, three hundred seventy-eight thousand, thirteen".