9658721 has 4 divisors (see below), whose sum is σ = 9664944. Its totient is φ = 9652500.

The previous prime is 9658709. The next prime is 9658723. The reversal of 9658721 is 1278569.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1278569 = 149 ⋅8581.

It is a cyclic number.

It is not a de Polignac number, because 9658721 - 2¹⁸ = 9396577 is a prime.

It is an Ulam number.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (9658723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1346 + ... + 4596.

It is an arithmetic number, because the mean of its divisors is an integer number (2416236).

Almost surely, 2^9658721 is an apocalyptic number.

It is an amenable number.

9658721 is a deficient number, since it is larger than the sum of its proper divisors (6223).

9658721 is a wasteful number, since it uses less digits than its factorization.

9658721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6222.

The product of its digits is 30240, while the sum is 38.

The square root of 9658721 is about 3107.8482910207. The cubic root of 9658721 is about 212.9641692174.

The spelling of 9658721 in words is "nine million, six hundred fifty-eight thousand, seven hundred twenty-one".