77785643 has 4 divisors (see below), whose sum is σ = 83769168. Its totient is φ = 71802120.

The previous prime is 77785637. The next prime is 77785709. The reversal of 77785643 is 34658777.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 77785643 - 2¹² = 77781547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77785613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2991743 + ... + 2991768.

It is an arithmetic number, because the mean of its divisors is an integer number (20942292).

Almost surely, 2^77785643 is an apocalyptic number.

77785643 is a deficient number, since it is larger than the sum of its proper divisors (5983525).

77785643 is a wasteful number, since it uses less digits than its factorization.

77785643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5983524.

The product of its digits is 987840, while the sum is 47.

The square root of 77785643 is about 8819.6169417951. The cubic root of 77785643 is about 426.8741098057.

The spelling of 77785643 in words is "seventy-seven million, seven hundred eighty-five thousand, six hundred forty-three".