77686789 has 4 divisors (see below), whose sum is σ = 78298624. Its totient is φ = 77074956.

The previous prime is 77686771. The next prime is 77686793. The reversal of 77686789 is 98768677.

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, and also an emirpimes, since its reverse is a distinct semiprime: 98768677 = 7 ⋅14109811.

It is a cyclic number.

It is not a de Polignac number, because 77686789 - 2¹¹ = 77684741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77686729) 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, 305727 + ... + 305980.

It is an arithmetic number, because the mean of its divisors is an integer number (19574656).

Almost surely, 2^77686789 is an apocalyptic number.

It is an amenable number.

77686789 is a deficient number, since it is larger than the sum of its proper divisors (611835).

77686789 is a wasteful number, since it uses less digits than its factorization.

77686789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 611834.

The product of its digits is 7112448, while the sum is 58.

The square root of 77686789 is about 8814.0109484842. The cubic root of 77686789 is about 426.6932019494.

The spelling of 77686789 in words is "seventy-seven million, six hundred eighty-six thousand, seven hundred eighty-nine".