66847077749 has 4 divisors (see below), whose sum is σ = 68653755564. Its totient is φ = 65040399936.

The previous prime is 66847077743. The next prime is 66847077751. The reversal of 66847077749 is 94777074866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26066102500 + 40780975249 = 161450^2 + 201943^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66847077749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66847077743) 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, 903338852 + ... + 903338925.

It is an arithmetic number, because the mean of its divisors is an integer number (17163438891).

Almost surely, 2^66847077749 is an apocalyptic number.

It is an amenable number.

66847077749 is a deficient number, since it is larger than the sum of its proper divisors (1806677815).

66847077749 is a wasteful number, since it uses less digits than its factorization.

66847077749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1806677814.

The product of its (nonzero) digits is 99574272, while the sum is 65.

The spelling of 66847077749 in words is "sixty-six billion, eight hundred forty-seven million, seventy-seven thousand, seven hundred forty-nine".