61165650661 has 4 divisors (see below), whose sum is σ = 61166276172. Its totient is φ = 61165025152.

The previous prime is 61165650583. The next prime is 61165650673. The reversal of 61165650661 is 16605656116.

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 26306893636 + 34858757025 = 162194^2 + 186705^2 .

It is a cyclic number.

It is not a de Polignac number, because 61165650661 - 2²⁹ = 60628779749 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 (61165650761) 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, 130786 + ... + 373411.

It is an arithmetic number, because the mean of its divisors is an integer number (15291569043).

Almost surely, 2^61165650661 is an apocalyptic number.

It is an amenable number.

61165650661 is a deficient number, since it is larger than the sum of its proper divisors (625511).

61165650661 is a wasteful number, since it uses less digits than its factorization.

61165650661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 625510.

The product of its (nonzero) digits is 194400, while the sum is 43.

The spelling of 61165650661 in words is "sixty-one billion, one hundred sixty-five million, six hundred fifty thousand, six hundred sixty-one".