66777601 has 10 divisors (see below), whose sum is σ = 73471010. Its totient is φ = 60693600.

The previous prime is 66777589. The next prime is 66777617. The reversal of 66777601 is 10677766.

66777601 is nontrivially palindromic in base 3.

It can be written as a sum of positive squares in only one way, i.e., 52707600 + 14070001 = 7260^2 + 3751^2 .

It is not a de Polignac number, because 66777601 - 2⁹ = 66777089 is a prime.

It is a super-3 number, since 3×66777601³ (a number of 24 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66777631) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 12361 + ... + 16921.

It is an arithmetic number, because the mean of its divisors is an integer number (7347101).

Almost surely, 2^66777601 is an apocalyptic number.

It is an amenable number.

66777601 is a deficient number, since it is larger than the sum of its proper divisors (6693409).

66777601 is an frugal number, since it uses more digits than its factorization.

66777601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4605 (or 4572 counting only the distinct ones).

The product of its (nonzero) digits is 74088, while the sum is 40.

The square root of 66777601 is about 8171.7562983731. The cubic root of 66777601 is about 405.7049167443.

The spelling of 66777601 in words is "sixty-six million, seven hundred seventy-seven thousand, six hundred one".