61777477717 has 2 divisors, whose sum is σ = 61777477718. Its totient is φ = 61777477716.

The previous prime is 61777477631. The next prime is 61777477771. The reversal of 61777477717 is 71777477716.

It is a happy number.

Together with next prime (61777477771) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49479998481 + 12297479236 = 222441^2 + 110894^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61777477717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61777477117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30888738858 + 30888738859.

It is an arithmetic number, because the mean of its divisors is an integer number (30888738859).

Almost surely, 2^61777477717 is an apocalyptic number.

It is an amenable number.

61777477717 is a deficient number, since it is larger than the sum of its proper divisors (1).

61777477717 is an equidigital number, since it uses as much as digits as its factorization.

61777477717 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19765032, while the sum is 61.

Subtracting 61777477717 from its reverse (71777477716), we obtain a palindrome (9999999999).

The spelling of 61777477717 in words is "sixty-one billion, seven hundred seventy-seven million, four hundred seventy-seven thousand, seven hundred seventeen".