43387640209 has 15 divisors (see below), whose sum is σ = 45877556427. Its totient is φ = 41032842624.

The previous prime is 43387640203. The next prime is 43387640221. The reversal of 43387640209 is 90204678334.

The square root of 43387640209 is 208297.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 43087380625 + 300259584 = 207575^2 + 17328^2 .

It is not a de Polignac number, because 43387640209 - 2⁷ = 43387640081 is a prime.

It is not an unprimeable number, because it can be changed into a prime (43387640203) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 75194929 + ... + 75195505.

Almost surely, 2^43387640209 is an apocalyptic number.

43387640209 is the 208297-th square number.

43387640209 is the 104149-th centered octagonal number.

It is an amenable number.

43387640209 is a deficient number, since it is larger than the sum of its proper divisors (2489916218).

43387640209 is an frugal number, since it uses more digits than its factorization.

43387640209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1230 (or 596 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 46.

The spelling of 43387640209 in words is "forty-three billion, three hundred eighty-seven million, six hundred forty thousand, two hundred nine".