661304409871 has 8 divisors (see below), whose sum is σ = 771856819200. Its totient is φ = 554772088248.

The previous prime is 661304409797. The next prime is 661304409893. The reversal of 661304409871 is 178904403166.

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

It is not a de Polignac number, because 661304409871 - 2¹¹ = 661304407823 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 (661304409371) 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 7 ways as a sum of consecutive naturals, for example, 1005021571 + ... + 1005022228.

It is an arithmetic number, because the mean of its divisors is an integer number (96482102400).

Almost surely, 2^661304409871 is an apocalyptic number.

661304409871 is a deficient number, since it is larger than the sum of its proper divisors (110552409329).

661304409871 is a wasteful number, since it uses less digits than its factorization.

661304409871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2010043853.

The product of its (nonzero) digits is 870912, while the sum is 49.

The spelling of 661304409871 in words is "six hundred sixty-one billion, three hundred four million, four hundred nine thousand, eight hundred seventy-one".