9911721 has 8 divisors (see below), whose sum is σ = 13396960. Its totient is φ = 6517152.

The previous prime is 9911717. The next prime is 9911743. The reversal of 9911721 is 1271199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 9911721 - 2² = 9911717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9911701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22411 + ... + 22848.

It is an arithmetic number, because the mean of its divisors is an integer number (1674620).

Almost surely, 2^9911721 is an apocalyptic number.

It is an amenable number.

9911721 is a deficient number, since it is larger than the sum of its proper divisors (3485239).

9911721 is a wasteful number, since it uses less digits than its factorization.

9911721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45335.

The product of its digits is 1134, while the sum is 30.

The square root of 9911721 is about 3148.2885827065. The cubic root of 9911721 is about 214.8076231217.

The spelling of 9911721 in words is "nine million, nine hundred eleven thousand, seven hundred twenty-one".