77220819761 has 2 divisors, whose sum is σ = 77220819762. Its totient is φ = 77220819760.

The previous prime is 77220819701. The next prime is 77220819763. The reversal of 77220819761 is 16791802277.

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., 69345322225 + 7875497536 = 263335^2 + 88744^2 .

It is an emirp because it is prime and its reverse (16791802277) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77220819761 - 2¹⁴ = 77220803377 is a prime.

Together with 77220819763, 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 (77220819763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38610409880 + 38610409881.

It is an arithmetic number, because the mean of its divisors is an integer number (38610409881).

Almost surely, 2^77220819761 is an apocalyptic number.

It is an amenable number.

77220819761 is a deficient number, since it is larger than the sum of its proper divisors (1).

77220819761 is an equidigital number, since it uses as much as digits as its factorization.

77220819761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 592704, while the sum is 50.

The spelling of 77220819761 in words is "seventy-seven billion, two hundred twenty million, eight hundred nineteen thousand, seven hundred sixty-one".