7756667561 has 2 divisors, whose sum is σ = 7756667562. Its totient is φ = 7756667560.

The previous prime is 7756667551. The next prime is 7756667579. The reversal of 7756667561 is 1657666577.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3936809536 + 3819858025 = 62744^2 + 61805^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7756667561 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 7756667497 and 7756667506.

It is not a weakly prime, because it can be changed into another prime (7756667551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3878333780 + 3878333781.

It is an arithmetic number, because the mean of its divisors is an integer number (3878333781).

Almost surely, 2^7756667561 is an apocalyptic number.

It is an amenable number.

7756667561 is a deficient number, since it is larger than the sum of its proper divisors (1).

7756667561 is an equidigital number, since it uses as much as digits as its factorization.

7756667561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11113200, while the sum is 56.

The square root of 7756667561 is about 88071.9453685451. The cubic root of 7756667561 is about 1979.5131579469.

The spelling of 7756667561 in words is "seven billion, seven hundred fifty-six million, six hundred sixty-seven thousand, five hundred sixty-one".