6551161661 has 16 divisors (see below), whose sum is σ = 7191160128. Its totient is φ = 5918668800.

The previous prime is 6551161609. The next prime is 6551161679. The reversal of 6551161661 is 1661611556.

It is not a de Polignac number, because 6551161661 - 2⁶ = 6551161597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6551161061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1598531 + ... + 1602623.

It is an arithmetic number, because the mean of its divisors is an integer number (449447508).

Almost surely, 2^6551161661 is an apocalyptic number.

It is an amenable number.

6551161661 is a deficient number, since it is larger than the sum of its proper divisors (639998467).

6551161661 is a wasteful number, since it uses less digits than its factorization.

6551161661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4972.

The product of its digits is 32400, while the sum is 38.

The square root of 6551161661 is about 80939.2467286421. The cubic root of 6551161661 is about 1871.1392355648.

The spelling of 6551161661 in words is "six billion, five hundred fifty-one million, one hundred sixty-one thousand, six hundred sixty-one".