77647989 has 4 divisors (see below), whose sum is σ = 103530656. Its totient is φ = 51765324.

The previous prime is 77647951. The next prime is 77648017. The reversal of 77647989 is 98974677.

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 not a de Polignac number, because 77647989 - 2²³ = 69259381 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77647909) 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, 12941329 + ... + 12941334.

It is an arithmetic number, because the mean of its divisors is an integer number (25882664).

Almost surely, 2^77647989 is an apocalyptic number.

It is an amenable number.

77647989 is a deficient number, since it is larger than the sum of its proper divisors (25882667).

77647989 is a wasteful number, since it uses less digits than its factorization.

77647989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25882666.

The product of its digits is 5334336, while the sum is 57.

The square root of 77647989 is about 8811.8096325329. The cubic root of 77647989 is about 426.6221540342.

It can be divided in two parts, 7764 and 7989, that added together give a triangular number (15753 = T₁₇₇).

The spelling of 77647989 in words is "seventy-seven million, six hundred forty-seven thousand, nine hundred eighty-nine".