61566056165 has 4 divisors (see below), whose sum is σ = 73879267404. Its totient is φ = 49252844928.

The previous prime is 61566056159. The next prime is 61566056177. The reversal of 61566056165 is 56165066516.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36506216356 + 25059839809 = 191066^2 + 158303^2 .

It is a cyclic number.

It is not a de Polignac number, because 61566056165 - 2¹² = 61566052069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6156605612 + ... + 6156605621.

It is an arithmetic number, because the mean of its divisors is an integer number (18469816851).

Almost surely, 2^61566056165 is an apocalyptic number.

It is an amenable number.

61566056165 is a deficient number, since it is larger than the sum of its proper divisors (12313211239).

61566056165 is a wasteful number, since it uses less digits than its factorization.

61566056165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12313211238.

The product of its (nonzero) digits is 972000, while the sum is 47.

The spelling of 61566056165 in words is "sixty-one billion, five hundred sixty-six million, fifty-six thousand, one hundred sixty-five".