61561517117 has 4 divisors (see below), whose sum is σ = 61562038236. Its totient is φ = 61560996000.

The previous prime is 61561517051. The next prime is 61561517159. The reversal of 61561517117 is 71171516516.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 44413876516 + 17147640601 = 210746^2 + 130949^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61561517117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61561516117) 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 in 3 ways as a sum of consecutive naturals, for example, 10943 + ... + 351059.

It is an arithmetic number, because the mean of its divisors is an integer number (15390509559).

Almost surely, 2^61561517117 is an apocalyptic number.

It is an amenable number.

61561517117 is a deficient number, since it is larger than the sum of its proper divisors (521119).

61561517117 is a wasteful number, since it uses less digits than its factorization.

61561517117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 521118.

The product of its digits is 44100, while the sum is 41.

The spelling of 61561517117 in words is "sixty-one billion, five hundred sixty-one million, five hundred seventeen thousand, one hundred seventeen".