61309780 has 72 divisors (see below), whose sum is σ = 151999848. Its totient is φ = 20708352.

The previous prime is 61309763. The next prime is 61309783. The reversal of 61309780 is 8790316.

61309780 is nontrivially palindromic in base 13.

61309780 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 20196036 + 41113744 = 4494^2 + 6412^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61309783) 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 in 23 ways as a sum of consecutive naturals, for example, 71112 + ... + 71968.

It is an arithmetic number, because the mean of its divisors is an integer number (2111109).

Almost surely, 2^61309780 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61309780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75999924).

61309780 is an abundant number, since it is smaller than the sum of its proper divisors (90690068).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61309780 is a wasteful number, since it uses less digits than its factorization.

61309780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 953 (or 944 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 61309780 is about 7830.0561939235. The cubic root of 61309780 is about 394.3149585484.

The spelling of 61309780 in words is "sixty-one million, three hundred nine thousand, seven hundred eighty".