6161616661 has 4 divisors (see below), whose sum is σ = 6195658924. Its totient is φ = 6127574400.

The previous prime is 6161616589. The next prime is 6161616677. The reversal of 6161616661 is 1666161616.

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 2913300625 + 3248316036 = 53975^2 + 56994^2 .

It is a cyclic number.

It is not a de Polignac number, because 6161616661 - 2²⁷ = 6027398933 is a prime.

It is a super-2 number, since 2×6161616661² = 75931039754225577842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6161616061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17020860 + ... + 17021221.

It is an arithmetic number, because the mean of its divisors is an integer number (1548914731).

Almost surely, 2^6161616661 is an apocalyptic number.

It is an amenable number.

6161616661 is a deficient number, since it is larger than the sum of its proper divisors (34042263).

6161616661 is a wasteful number, since it uses less digits than its factorization.

6161616661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34042262.

The product of its digits is 46656, while the sum is 40.

The square root of 6161616661 is about 78495.9658899742. The cubic root of 6161616661 is about 1833.2916421998.

The spelling of 6161616661 in words is "six billion, one hundred sixty-one million, six hundred sixteen thousand, six hundred sixty-one".