6561161616518 has 16 divisors (see below), whose sum is σ = 9910107868320. Its totient is φ = 3257868163200.

The previous prime is 6561161616517. The next prime is 6561161616643. The reversal of 6561161616518 is 8156161611656.

It is a super-5 number, since 5×6561161616518⁵ (a number of 65 digits) contains 55555 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 6561161616518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561161616511) 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, 18785693 + ... + 19131768.

It is an arithmetic number, because the mean of its divisors is an integer number (619381741770).

Almost surely, 2^{6561161616518} is an apocalyptic number.

6561161616518 is a deficient number, since it is larger than the sum of its proper divisors (3348946251802).

6561161616518 is a wasteful number, since it uses less digits than its factorization.

6561161616518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37918063.

The product of its digits is 1555200, while the sum is 53.

The spelling of 6561161616518 in words is "six trillion, five hundred sixty-one billion, one hundred sixty-one million, six hundred sixteen thousand, five hundred eighteen".