77457728549 has 2 divisors, whose sum is σ = 77457728550. Its totient is φ = 77457728548.

The previous prime is 77457728501. The next prime is 77457728561. The reversal of 77457728549 is 94582775477.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65326248100 + 12131480449 = 255590^2 + 110143^2 .

It is an emirp because it is prime and its reverse (94582775477) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77457728549 - 2¹² = 77457724453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77457722549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38728864274 + 38728864275.

It is an arithmetic number, because the mean of its divisors is an integer number (38728864275).

Almost surely, 2^77457728549 is an apocalyptic number.

It is an amenable number.

77457728549 is a deficient number, since it is larger than the sum of its proper divisors (1).

77457728549 is an equidigital number, since it uses as much as digits as its factorization.

77457728549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138297600, while the sum is 65.

The spelling of 77457728549 in words is "seventy-seven billion, four hundred fifty-seven million, seven hundred twenty-eight thousand, five hundred forty-nine".