43509666816 has 792 divisors, whose sum is σ = 168185777760. Its totient is φ = 10683187200.

The previous prime is 43509666751. The next prime is 43509666821. The reversal of 43509666816 is 61866690534.

It is a tau number, because it is divible by the number of its divisors (792).

It is a super-2 number, since 2×43509666816² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 94380826 + ... + 94381286.

It is an arithmetic number, because the mean of its divisors is an integer number (212355780).

Almost surely, 2^43509666816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 43509666816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84092888880).

43509666816 is an abundant number, since it is smaller than the sum of its proper divisors (124676110944).

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

43509666816 is a wasteful number, since it uses less digits than its factorization.

43509666816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 531 (or 503 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 54.

The spelling of 43509666816 in words is "forty-three billion, five hundred nine million, six hundred sixty-six thousand, eight hundred sixteen".