66771977 has 4 divisors (see below), whose sum is σ = 66985620. Its totient is φ = 66558336.

The previous prime is 66771973. The next prime is 66771989. The reversal of 66771977 is 77917766.

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 22429696 + 44342281 = 4736^2 + 6659^2 .

It is a cyclic number.

It is not a de Polignac number, because 66771977 - 2² = 66771973 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66771973) 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, 106352 + ... + 106977.

It is an arithmetic number, because the mean of its divisors is an integer number (16746405).

Almost surely, 2^66771977 is an apocalyptic number.

It is an amenable number.

66771977 is a deficient number, since it is larger than the sum of its proper divisors (213643).

66771977 is a wasteful number, since it uses less digits than its factorization.

66771977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213642.

The product of its digits is 777924, while the sum is 50.

The square root of 66771977 is about 8171.4121790545. The cubic root of 66771977 is about 405.6935269546.

The spelling of 66771977 in words is "sixty-six million, seven hundred seventy-one thousand, nine hundred seventy-seven".