77648789 has 2 divisors, whose sum is σ = 77648790. Its totient is φ = 77648788.

The previous prime is 77648783. The next prime is 77648797. The reversal of 77648789 is 98784677.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65691025 + 11957764 = 8105^2 + 3458^2 .

It is an emirp because it is prime and its reverse (98784677) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77648789 - 2²⁰ = 76600213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77648783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38824394 + 38824395.

It is an arithmetic number, because the mean of its divisors is an integer number (38824395).

Almost surely, 2^77648789 is an apocalyptic number.

It is an amenable number.

77648789 is a deficient number, since it is larger than the sum of its proper divisors (1).

77648789 is an equidigital number, since it uses as much as digits as its factorization.

77648789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4741632, while the sum is 56.

The square root of 77648789 is about 8811.8550260430. The cubic root of 77648789 is about 426.6236191786.

The spelling of 77648789 in words is "seventy-seven million, six hundred forty-eight thousand, seven hundred eighty-nine".