56516001661 has 6 divisors (see below), whose sum is σ = 65743104030. Its totient is φ = 48442287096.

The previous prime is 56516001623. The next prime is 56516001667. The reversal of 56516001661 is 16610061565.

It can be written as a sum of positive squares in only one way, i.e., 53225258436 + 3290743225 = 230706^2 + 57365^2 .

It is not a de Polignac number, because 56516001661 - 2¹⁵ = 56515968893 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 56516001661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56516001667) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 576693846 + ... + 576693943.

It is an arithmetic number, because the mean of its divisors is an integer number (10957184005).

Almost surely, 2^56516001661 is an apocalyptic number.

It is an amenable number.

56516001661 is a deficient number, since it is larger than the sum of its proper divisors (9227102369).

56516001661 is a wasteful number, since it uses less digits than its factorization.

56516001661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1153387803 (or 1153387796 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 37.

The spelling of 56516001661 in words is "fifty-six billion, five hundred sixteen million, one thousand, six hundred sixty-one".