6661531643 has 6 divisors (see below), whose sum is σ = 7213374684. Its totient is φ = 6149105976.

The previous prime is 6661531603. The next prime is 6661531661. The reversal of 6661531643 is 3461351666.

It is not a de Polignac number, because 6661531643 - 2⁶ = 6661531579 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6661531643.

It is not an unprimeable number, because it can be changed into a prime (6661531603) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19708505 + ... + 19708842.

It is an arithmetic number, because the mean of its divisors is an integer number (1202229114).

Almost surely, 2^6661531643 is an apocalyptic number.

6661531643 is a deficient number, since it is larger than the sum of its proper divisors (551843041).

6661531643 is a wasteful number, since it uses less digits than its factorization.

6661531643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39417373 (or 39417360 counting only the distinct ones).

The product of its digits is 233280, while the sum is 41.

The square root of 6661531643 is about 81618.2065656922. The cubic root of 6661531643 is about 1881.5887094126.

The spelling of 6661531643 in words is "six billion, six hundred sixty-one million, five hundred thirty-one thousand, six hundred forty-three".