77939194609 has 2 divisors, whose sum is σ = 77939194610. Its totient is φ = 77939194608.

The previous prime is 77939194601. The next prime is 77939194631. The reversal of 77939194609 is 90649193977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50964417009 + 26974777600 = 225753^2 + 164240^2 .

It is an emirp because it is prime and its reverse (90649193977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77939194609 - 2³ = 77939194601 is a prime.

It is not a weakly prime, because it can be changed into another prime (77939194601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38969597304 + 38969597305.

It is an arithmetic number, because the mean of its divisors is an integer number (38969597305).

Almost surely, 2^77939194609 is an apocalyptic number.

It is an amenable number.

77939194609 is a deficient number, since it is larger than the sum of its proper divisors (1).

77939194609 is an equidigital number, since it uses as much as digits as its factorization.

77939194609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23147208, while the sum is 64.

The spelling of 77939194609 in words is "seventy-seven billion, nine hundred thirty-nine million, one hundred ninety-four thousand, six hundred nine".