66776785 has 8 divisors (see below), whose sum is σ = 80841960. Its totient is φ = 52948224.

The previous prime is 66776783. The next prime is 66776791. The reversal of 66776785 is 58767766.

It can be written as a sum of positive squares in 4 ways, for example, as 5326864 + 61449921 = 2308^2 + 7839^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66776785 - 2¹ = 66776783 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66776783) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58530 + ... + 59659.

It is an arithmetic number, because the mean of its divisors is an integer number (10105245).

Almost surely, 2^66776785 is an apocalyptic number.

It is an amenable number.

66776785 is a deficient number, since it is larger than the sum of its proper divisors (14065175).

66776785 is a wasteful number, since it uses less digits than its factorization.

66776785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118307.

The product of its digits is 2963520, while the sum is 52.

The square root of 66776785 is about 8171.7063701531. The cubic root of 66776785 is about 405.7032642114.

The spelling of 66776785 in words is "sixty-six million, seven hundred seventy-six thousand, seven hundred eighty-five".