66964815 has 24 divisors (see below), whose sum is σ = 117477360. Its totient is φ = 35282304.

The previous prime is 66964813. The next prime is 66964837. The reversal of 66964815 is 51846966.

It is not a de Polignac number, because 66964815 - 2¹ = 66964813 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66964813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5230 + ... + 12699.

It is an arithmetic number, because the mean of its divisors is an integer number (4894890).

Almost surely, 2^66964815 is an apocalyptic number.

66964815 is a deficient number, since it is larger than the sum of its proper divisors (50512545).

66964815 is a wasteful number, since it uses less digits than its factorization.

66964815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18023 (or 18020 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The square root of 66964815 is about 8183.2032236771. The cubic root of 66964815 is about 406.0837002969.

It can be divided in two parts, 6696 and 4815, that added together give a palindrome (11511).

The spelling of 66964815 in words is "sixty-six million, nine hundred sixty-four thousand, eight hundred fifteen".