61309709 has 2 divisors, whose sum is σ = 61309710. Its totient is φ = 61309708.

The previous prime is 61309687. The next prime is 61309739. The reversal of 61309709 is 90790316.

61309709 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61183684 + 126025 = 7822^2 + 355^2 .

It is a cyclic number.

It is not a de Polignac number, because 61309709 - 2¹² = 61305613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61309739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30654854 + 30654855.

It is an arithmetic number, because the mean of its divisors is an integer number (30654855).

Almost surely, 2^61309709 is an apocalyptic number.

It is an amenable number.

61309709 is a deficient number, since it is larger than the sum of its proper divisors (1).

61309709 is an equidigital number, since it uses as much as digits as its factorization.

61309709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10206, while the sum is 35.

The square root of 61309709 is about 7830.0516601106. The cubic root of 61309709 is about 394.3148063358.

The spelling of 61309709 in words is "sixty-one million, three hundred nine thousand, seven hundred nine".