77801609 has 2 divisors, whose sum is σ = 77801610. Its totient is φ = 77801608.

The previous prime is 77801579. The next prime is 77801611. The reversal of 77801609 is 90610877.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45630025 + 32171584 = 6755^2 + 5672^2 .

It is a cyclic number.

It is not a de Polignac number, because 77801609 - 2¹² = 77797513 is a prime.

Together with 77801611, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77801629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38900804 + 38900805.

It is an arithmetic number, because the mean of its divisors is an integer number (38900805).

Almost surely, 2^77801609 is an apocalyptic number.

It is an amenable number.

77801609 is a deficient number, since it is larger than the sum of its proper divisors (1).

77801609 is an equidigital number, since it uses as much as digits as its factorization.

77801609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21168, while the sum is 38.

The square root of 77801609 is about 8820.5220367051. The cubic root of 77801609 is about 426.9033140201.

The spelling of 77801609 in words is "seventy-seven million, eight hundred one thousand, six hundred nine".