9721791 has 6 divisors (see below), whose sum is σ = 14042600. Its totient is φ = 6481188.

The previous prime is 9721783. The next prime is 9721793. The reversal of 9721791 is 1971279.

It is not a de Polignac number, because 9721791 - 2³ = 9721783 is a prime.

It is a Duffinian number.

9721791 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9721793) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 540091 + ... + 540108.

Almost surely, 2^9721791 is an apocalyptic number.

9721791 is a deficient number, since it is larger than the sum of its proper divisors (4320809).

9721791 is a wasteful number, since it uses less digits than its factorization.

9721791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1080205 (or 1080202 counting only the distinct ones).

The product of its digits is 7938, while the sum is 36.

The square root of 9721791 is about 3117.9786721528. The cubic root of 9721791 is about 213.4267052749.

The spelling of 9721791 in words is "nine million, seven hundred twenty-one thousand, seven hundred ninety-one".