66777761 has 8 divisors (see below), whose sum is σ = 71342880. Its totient is φ = 62317728.

The previous prime is 66777713. The next prime is 66777779. The reversal of 66777761 is 16777766.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66777761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66777461) 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, 24956 + ... + 27501.

It is an arithmetic number, because the mean of its divisors is an integer number (8917860).

Almost surely, 2^66777761 is an apocalyptic number.

It is an amenable number.

66777761 is a deficient number, since it is larger than the sum of its proper divisors (4565119).

66777761 is a wasteful number, since it uses less digits than its factorization.

66777761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52543.

The product of its digits is 518616, while the sum is 47.

The square root of 66777761 is about 8171.7660881844. The cubic root of 66777761 is about 405.7052407688.

The spelling of 66777761 in words is "sixty-six million, seven hundred seventy-seven thousand, seven hundred sixty-one".