77126561 has 2 divisors, whose sum is σ = 77126562. Its totient is φ = 77126560.

The previous prime is 77126551. The next prime is 77126579. The reversal of 77126561 is 16562177.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63760225 + 13366336 = 7985^2 + 3656^2 .

It is an emirp because it is prime and its reverse (16562177) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77126561 is a prime.

It is not a weakly prime, because it can be changed into another prime (77126531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38563280 + 38563281.

It is an arithmetic number, because the mean of its divisors is an integer number (38563281).

Almost surely, 2^77126561 is an apocalyptic number.

It is an amenable number.

77126561 is a deficient number, since it is larger than the sum of its proper divisors (1).

77126561 is an equidigital number, since it uses as much as digits as its factorization.

77126561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17640, while the sum is 35.

The square root of 77126561 is about 8782.1729087965. The cubic root of 77126561 is about 425.6650459811.

The spelling of 77126561 in words is "seventy-seven million, one hundred twenty-six thousand, five hundred sixty-one".