8661345920 has 64 divisors (see below), whose sum is σ = 20813612040. Its totient is φ = 3446538240.

The previous prime is 8661345919. The next prime is 8661345923. The reversal of 8661345920 is 295431668.

It can be written as a sum of positive squares in 4 ways, for example, as 3728812096 + 4932533824 = 61064^2 + 70232^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (8661345923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88460 + ... + 158580.

Almost surely, 2^8661345920 is an apocalyptic number.

8661345920 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 8661345920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10406806020).

8661345920 is an abundant number, since it is smaller than the sum of its proper divisors (12152266120).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

8661345920 is a wasteful number, since it uses less digits than its factorization.

8661345920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70333 (or 70321 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 44.

The square root of 8661345920 is about 93066.3522439770. The cubic root of 8661345920 is about 2053.6596078288.

The spelling of 8661345920 in words is "eight billion, six hundred sixty-one million, three hundred forty-five thousand, nine hundred twenty".