77606015521 has 2 divisors, whose sum is σ = 77606015522. Its totient is φ = 77606015520.

The previous prime is 77606015503. The next prime is 77606015551. The reversal of 77606015521 is 12551060677.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64432714896 + 13173300625 = 253836^2 + 114775^2 .

It is an emirp because it is prime and its reverse (12551060677) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77606015521 - 2¹³ = 77606007329 is a prime.

It is not a weakly prime, because it can be changed into another prime (77606015551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38803007760 + 38803007761.

It is an arithmetic number, because the mean of its divisors is an integer number (38803007761).

Almost surely, 2^77606015521 is an apocalyptic number.

It is an amenable number.

77606015521 is a deficient number, since it is larger than the sum of its proper divisors (1).

77606015521 is an equidigital number, since it uses as much as digits as its factorization.

77606015521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 88200, while the sum is 40.

The spelling of 77606015521 in words is "seventy-seven billion, six hundred six million, fifteen thousand, five hundred twenty-one".