6661543265 has 16 divisors (see below), whose sum is σ = 8818736976. Its totient is φ = 4799308800.

The previous prime is 6661543253. The next prime is 6661543271. The reversal of 6661543265 is 5623451666.

It can be written as a sum of positive squares in 8 ways, for example, as 279290944 + 6382252321 = 16712^2 + 79889^2 .

It is not a de Polignac number, because 6661543265 - 2⁶ = 6661543201 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1247156 + ... + 1252485.

It is an arithmetic number, because the mean of its divisors is an integer number (551171061).

Almost surely, 2^6661543265 is an apocalyptic number.

6661543265 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

6661543265 is a deficient number, since it is larger than the sum of its proper divisors (2157193711).

6661543265 is a wasteful number, since it uses less digits than its factorization.

6661543265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2499700.

The product of its digits is 777600, while the sum is 44.

The square root of 6661543265 is about 81618.2777630109. The cubic root of 6661543265 is about 1881.5898036460.

The spelling of 6661543265 in words is "six billion, six hundred sixty-one million, five hundred forty-three thousand, two hundred sixty-five".