61544351221 has 2 divisors, whose sum is σ = 61544351222. Its totient is φ = 61544351220.

The previous prime is 61544351179. The next prime is 61544351227. The reversal of 61544351221 is 12215344516.

61544351221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39990000625 + 21554350596 = 199975^2 + 146814^2 .

It is a cyclic number.

It is not a de Polignac number, because 61544351221 - 2⁹ = 61544350709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61544351227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30772175610 + 30772175611.

It is an arithmetic number, because the mean of its divisors is an integer number (30772175611).

Almost surely, 2^61544351221 is an apocalyptic number.

It is an amenable number.

61544351221 is a deficient number, since it is larger than the sum of its proper divisors (1).

61544351221 is an equidigital number, since it uses as much as digits as its factorization.

61544351221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28800, while the sum is 34.

Adding to 61544351221 its reverse (12215344516), we get a palindrome (73759695737).

The spelling of 61544351221 in words is "sixty-one billion, five hundred forty-four million, three hundred fifty-one thousand, two hundred twenty-one".