77556413552561 has 4 divisors (see below), whose sum is σ = 77556503995392. Its totient is φ = 77556323109732.

The previous prime is 77556413552521. The next prime is 77556413552591. The reversal of 77556413552561 is 16525531465577.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 77556413552561 - 2¹⁰ = 77556413551537 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 77556413552494 and 77556413552503.

It is not an unprimeable number, because it can be changed into a prime (77556413552521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43922705 + ... + 45654318.

It is an arithmetic number, because the mean of its divisors is an integer number (19389125998848).

Almost surely, 2^{77556413552561} is an apocalyptic number.

It is an amenable number.

77556413552561 is a deficient number, since it is larger than the sum of its proper divisors (90442831).

77556413552561 is an equidigital number, since it uses as much as digits as its factorization.

77556413552561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90442830.

The product of its digits is 132300000, while the sum is 62.

The spelling of 77556413552561 in words is "seventy-seven trillion, five hundred fifty-six billion, four hundred thirteen million, five hundred fifty-two thousand, five hundred sixty-one".