61696185721 has 2 divisors, whose sum is σ = 61696185722. Its totient is φ = 61696185720.

The previous prime is 61696185703. The next prime is 61696185739. The reversal of 61696185721 is 12758169616.

It is a balanced prime because it is at equal distance from previous prime (61696185703) and next prime (61696185739).

It can be written as a sum of positive squares in only one way, i.e., 49700460096 + 11995725625 = 222936^2 + 109525^2 .

It is a cyclic number.

It is not a de Polignac number, because 61696185721 - 2¹⁵ = 61696152953 is a prime.

It is not a weakly prime, because it can be changed into another prime (61696125721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30848092860 + 30848092861.

It is an arithmetic number, because the mean of its divisors is an integer number (30848092861).

Almost surely, 2^61696185721 is an apocalyptic number.

It is an amenable number.

61696185721 is a deficient number, since it is larger than the sum of its proper divisors (1).

61696185721 is an equidigital number, since it uses as much as digits as its factorization.

61696185721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 52.

The spelling of 61696185721 in words is "sixty-one billion, six hundred ninety-six million, one hundred eighty-five thousand, seven hundred twenty-one".