43398963908521 has 45 divisors (see below), whose sum is σ = 49965503960841. Its totient is φ = 37687634120448.

The previous prime is 43398963908473. The next prime is 43398963908527. The reversal of 43398963908521 is 12580936989334.

The square root of 43398963908521 is 6587789.

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

It can be written as a sum of positive squares in 22 ways, for example, as 25284917184921 + 18114046723600 = 5028411^2 + 4256060^2 .

It is not a de Polignac number, because 43398963908521 - 2¹⁹ = 43398963384233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43398963908527) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 18926716651 + ... + 18926718943.

Almost surely, 2^{43398963908521} is an apocalyptic number.

43398963908521 is the 6587789-th square number.

43398963908521 is the 3293895-th centered octagonal number.

It is an amenable number.

43398963908521 is a deficient number, since it is larger than the sum of its proper divisors (6566540052320).

43398963908521 is an frugal number, since it uses more digits than its factorization.

43398963908521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4672 (or 2323 counting only the distinct ones).

The product of its (nonzero) digits is 302330880, while the sum is 70.

The spelling of 43398963908521 in words is "forty-three trillion, three hundred ninety-eight billion, nine hundred sixty-three million, nine hundred eight thousand, five hundred twenty-one".