66117977 has 4 divisors (see below), whose sum is σ = 67365540. Its totient is φ = 64870416.

The previous prime is 66117973. The next prime is 66118007. The reversal of 66117977 is 77971166.

It is a happy number.

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 52693081 + 13424896 = 7259^2 + 3664^2 .

It is a cyclic number.

It is not a de Polignac number, because 66117977 - 2² = 66117973 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66117971) 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, 623702 + ... + 623807.

It is an arithmetic number, because the mean of its divisors is an integer number (16841385).

Almost surely, 2^66117977 is an apocalyptic number.

It is an amenable number.

66117977 is a deficient number, since it is larger than the sum of its proper divisors (1247563).

66117977 is a wasteful number, since it uses less digits than its factorization.

66117977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1247562.

The product of its digits is 111132, while the sum is 44.

The square root of 66117977 is about 8131.2961451419. The cubic root of 66117977 is about 404.3646533619.

The spelling of 66117977 in words is "sixty-six million, one hundred seventeen thousand, nine hundred seventy-seven".