7611666515561 has 2 divisors, whose sum is σ = 7611666515562. Its totient is φ = 7611666515560.

The previous prime is 7611666515549. The next prime is 7611666515581. The reversal of 7611666515561 is 1655156661167.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4836177155161 + 2775489360400 = 2199131^2 + 1665980^2 .

It is a cyclic number.

It is not a de Polignac number, because 7611666515561 - 2³⁰ = 7610592773737 is a prime.

It is a super-2 number, since 2×7611666515561² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 7611666515497 and 7611666515506.

It is not a weakly prime, because it can be changed into another prime (7611666515521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3805833257780 + 3805833257781.

It is an arithmetic number, because the mean of its divisors is an integer number (3805833257781).

Almost surely, 2^{7611666515561} is an apocalyptic number.

It is an amenable number.

7611666515561 is a deficient number, since it is larger than the sum of its proper divisors (1).

7611666515561 is an equidigital number, since it uses as much as digits as its factorization.

7611666515561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6804000, while the sum is 56.

It can be divided in two parts, 761166 and 6515561, that added together give a palindrome (7276727).

The spelling of 7611666515561 in words is "seven trillion, six hundred eleven billion, six hundred sixty-six million, five hundred fifteen thousand, five hundred sixty-one".