61317216561 has 8 divisors (see below), whose sum is σ = 81760312000. Its totient is φ = 40876132752.

The previous prime is 61317216511. The next prime is 61317216607. The reversal of 61317216561 is 16561271316.

61317216561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 61317216561 - 2¹⁰ = 61317215537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61317216511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 430285 + ... + 554778.

It is an arithmetic number, because the mean of its divisors is an integer number (10220039000).

Almost surely, 2^61317216561 is an apocalyptic number.

It is an amenable number.

61317216561 is a deficient number, since it is larger than the sum of its proper divisors (20443095439).

61317216561 is a wasteful number, since it uses less digits than its factorization.

61317216561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1005815.

The product of its digits is 45360, while the sum is 39.

Adding to 61317216561 its reverse (16561271316), we get a palindrome (77878487877).

The spelling of 61317216561 in words is "sixty-one billion, three hundred seventeen million, two hundred sixteen thousand, five hundred sixty-one".