77686561 has 4 divisors (see below), whose sum is σ = 77746432. Its totient is φ = 77626692.

The previous prime is 77686541. The next prime is 77686577. The reversal of 77686561 is 16568677.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 77686561 - 2¹¹ = 77684513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77686541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27945 + ... + 30598.

It is an arithmetic number, because the mean of its divisors is an integer number (19436608).

Almost surely, 2^77686561 is an apocalyptic number.

It is an amenable number.

77686561 is a deficient number, since it is larger than the sum of its proper divisors (59871).

77686561 is a wasteful number, since it uses less digits than its factorization.

77686561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59870.

The product of its digits is 423360, while the sum is 46.

The square root of 77686561 is about 8813.9980145221. The cubic root of 77686561 is about 426.6927845204.

The spelling of 77686561 in words is "seventy-seven million, six hundred eighty-six thousand, five hundred sixty-one".