71561773 has 2 divisors, whose sum is σ = 71561774. Its totient is φ = 71561772.

The previous prime is 71561753. The next prime is 71561797. The reversal of 71561773 is 37716517.

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., 60419529 + 11142244 = 7773^2 + 3338^2 .

It is a cyclic number.

It is not a de Polignac number, because 71561773 - 2⁵ = 71561741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71561753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35780886 + 35780887.

It is an arithmetic number, because the mean of its divisors is an integer number (35780887).

Almost surely, 2^71561773 is an apocalyptic number.

It is an amenable number.

71561773 is a deficient number, since it is larger than the sum of its proper divisors (1).

71561773 is an equidigital number, since it uses as much as digits as its factorization.

71561773 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30870, while the sum is 37.

The square root of 71561773 is about 8459.4191881003. The cubic root of 71561773 is about 415.1710196576.

The spelling of 71561773 in words is "seventy-one million, five hundred sixty-one thousand, seven hundred seventy-three".