61811505121 has 2 divisors, whose sum is σ = 61811505122. Its totient is φ = 61811505120.

The previous prime is 61811505047. The next prime is 61811505149. The reversal of 61811505121 is 12150511816.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31408700625 + 30402804496 = 177225^2 + 174364^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61811505121 is a prime.

It is not a weakly prime, because it can be changed into another prime (61811505191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30905752560 + 30905752561.

It is an arithmetic number, because the mean of its divisors is an integer number (30905752561).

Almost surely, 2^61811505121 is an apocalyptic number.

It is an amenable number.

61811505121 is a deficient number, since it is larger than the sum of its proper divisors (1).

61811505121 is an equidigital number, since it uses as much as digits as its factorization.

61811505121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2400, while the sum is 31.

The spelling of 61811505121 in words is "sixty-one billion, eight hundred eleven million, five hundred five thousand, one hundred twenty-one".