77905109 has 2 divisors, whose sum is σ = 77905110. Its totient is φ = 77905108.

The previous prime is 77905103. The next prime is 77905123. The reversal of 77905109 is 90150977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41242084 + 36663025 = 6422^2 + 6055^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77905109 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77905103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38952554 + 38952555.

It is an arithmetic number, because the mean of its divisors is an integer number (38952555).

Almost surely, 2^77905109 is an apocalyptic number.

It is an amenable number.

77905109 is a deficient number, since it is larger than the sum of its proper divisors (1).

77905109 is an equidigital number, since it uses as much as digits as its factorization.

77905109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19845, while the sum is 38.

The square root of 77905109 is about 8826.3870864584. The cubic root of 77905109 is about 427.0925342477.

The spelling of 77905109 in words is "seventy-seven million, nine hundred five thousand, one hundred nine".