61121766721 has 2 divisors, whose sum is σ = 61121766722. Its totient is φ = 61121766720.

The previous prime is 61121766709. The next prime is 61121766763. The reversal of 61121766721 is 12766712116.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55592208400 + 5529558321 = 235780^2 + 74361^2 .

It is a cyclic number.

It is not a de Polignac number, because 61121766721 - 2⁵ = 61121766689 is a prime.

It is not a weakly prime, because it can be changed into another prime (61121761721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30560883360 + 30560883361.

It is an arithmetic number, because the mean of its divisors is an integer number (30560883361).

Almost surely, 2^61121766721 is an apocalyptic number.

It is an amenable number.

61121766721 is a deficient number, since it is larger than the sum of its proper divisors (1).

61121766721 is an equidigital number, since it uses as much as digits as its factorization.

61121766721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42336, while the sum is 40.

The spelling of 61121766721 in words is "sixty-one billion, one hundred twenty-one million, seven hundred sixty-six thousand, seven hundred twenty-one".