61391440650 has 96 divisors (see below), whose sum is σ = 154003268160. Its totient is φ = 16183019520.

The previous prime is 61391440589. The next prime is 61391440673. The reversal of 61391440650 is 5604419316.

It is a junction number, because it is equal to n+sod(n) for n = 61391440599 and 61391440608.

It is an unprimeable number.

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 in 47 ways as a sum of consecutive naturals, for example, 15551977 + ... + 15555923.

It is an arithmetic number, because the mean of its divisors is an integer number (1604200710).

Almost surely, 2^61391440650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61391440650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77001634080).

61391440650 is an abundant number, since it is smaller than the sum of its proper divisors (92611827510).

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

61391440650 is a wasteful number, since it uses less digits than its factorization.

61391440650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5128 (or 5123 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 39.

Adding to 61391440650 its reverse (5604419316), we get a palindrome (66995859966).

The spelling of 61391440650 in words is "sixty-one billion, three hundred ninety-one million, four hundred forty thousand, six hundred fifty".