916721 has 8 divisors (see below), whose sum is σ = 995904. Its totient is φ = 838800.

The previous prime is 916703. The next prime is 916733. The reversal of 916721 is 127619.

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

It is a cyclic number.

It is not a de Polignac number, because 916721 - 2¹⁰ = 915697 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 916721.

It is not an unprimeable number, because it can be changed into a prime (916771) 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, 1730 + ... + 2196.

It is an arithmetic number, because the mean of its divisors is an integer number (124488).

2⁹¹⁶⁷²¹ is an apocalyptic number.

It is an amenable number.

916721 is a deficient number, since it is larger than the sum of its proper divisors (79183).

916721 is a wasteful number, since it uses less digits than its factorization.

916721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 631.

The product of its digits is 756, while the sum is 26.

The square root of 916721 is about 957.4554819938. The cubic root of 916721 is about 97.1431972924.

The spelling of 916721 in words is "nine hundred sixteen thousand, seven hundred twenty-one".