77558499372661 has 2 divisors, whose sum is σ = 77558499372662. Its totient is φ = 77558499372660.

The previous prime is 77558499372619. The next prime is 77558499372667. The reversal of 77558499372661 is 16627399485577.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75235344216561 + 2323155156100 = 8673831^2 + 1524190^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77558499372661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77558499372667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38779249686330 + 38779249686331.

It is an arithmetic number, because the mean of its divisors is an integer number (38779249686331).

Almost surely, 2^{77558499372661} is an apocalyptic number.

It is an amenable number.

77558499372661 is a deficient number, since it is larger than the sum of its proper divisors (1).

77558499372661 is an equidigital number, since it uses as much as digits as its factorization.

77558499372661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4800902400, while the sum is 79.

The spelling of 77558499372661 in words is "seventy-seven trillion, five hundred fifty-eight billion, four hundred ninety-nine million, three hundred seventy-two thousand, six hundred sixty-one".