9721368409 has 3 divisors (see below), whose sum is σ = 9721467007. Its totient is φ = 9721269812.

The previous prime is 9721368407. The next prime is 9721368479. The reversal of 9721368409 is 9048631279.

The square root of 9721368409 is 98597.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 9048631279 = 113 ⋅80076383.

It can be written as a sum of positive squares in only one way, i.e., 9720974025 + 394384 = 98595^2 + 628^2 .

It is not a de Polignac number, because 9721368409 - 2¹ = 9721368407 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9721368401) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 49299 + ... + 147895.

Almost surely, 2^9721368409 is an apocalyptic number.

9721368409 is the 98597-th square number.

9721368409 is the 49299-th centered octagonal number.

It is an amenable number.

9721368409 is a deficient number, since it is larger than the sum of its proper divisors (98598).

9721368409 is an frugal number, since it uses more digits than its factorization.

9721368409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197194 (or 98597 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 49.

The cubic root of 9721368409 is about 2134.2361278878.

Multiplying 9721368409 by its sum of digits (49), we get a square (476347052041 = 690179²).

The spelling of 9721368409 in words is "nine billion, seven hundred twenty-one million, three hundred sixty-eight thousand, four hundred nine".