61778876481817 has 4 divisors (see below), whose sum is σ = 67395137980176. Its totient is φ = 56162614983460.

The previous prime is 61778876481781. The next prime is 61778876481877. The reversal of 61778876481817 is 71818467887716.

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 61778876481817 - 2³⁹ = 61229120667929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61778876481877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2808130749163 + ... + 2808130749184.

It is an arithmetic number, because the mean of its divisors is an integer number (16848784495044).

Almost surely, 2^{61778876481817} is an apocalyptic number.

It is an amenable number.

61778876481817 is a deficient number, since it is larger than the sum of its proper divisors (5616261498359).

61778876481817 is a wasteful number, since it uses less digits than its factorization.

61778876481817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5616261498358.

The product of its digits is 1416167424, while the sum is 79.

The spelling of 61778876481817 in words is "sixty-one trillion, seven hundred seventy-eight billion, eight hundred seventy-six million, four hundred eighty-one thousand, eight hundred seventeen".