71513566561 has 2 divisors, whose sum is σ = 71513566562. Its totient is φ = 71513566560.

The previous prime is 71513566549. The next prime is 71513566577. The reversal of 71513566561 is 16566531517.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62113100625 + 9400465936 = 249225^2 + 96956^2 .

It is a cyclic number.

It is not a de Polignac number, because 71513566561 - 2⁵ = 71513566529 is a prime.

It is a super-2 number, since 2×71513566561² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (71513566361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35756783280 + 35756783281.

It is an arithmetic number, because the mean of its divisors is an integer number (35756783281).

Almost surely, 2^71513566561 is an apocalyptic number.

It is an amenable number.

71513566561 is a deficient number, since it is larger than the sum of its proper divisors (1).

71513566561 is an equidigital number, since it uses as much as digits as its factorization.

71513566561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 567000, while the sum is 46.

The spelling of 71513566561 in words is "seventy-one billion, five hundred thirteen million, five hundred sixty-six thousand, five hundred sixty-one".