9712821 has 4 divisors (see below), whose sum is σ = 12950432. Its totient is φ = 6475212.

The previous prime is 9712817. The next prime is 9712849. The reversal of 9712821 is 1282179.

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.

It is not a de Polignac number, because 9712821 - 2² = 9712817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9712811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1618801 + ... + 1618806.

It is an arithmetic number, because the mean of its divisors is an integer number (3237608).

Almost surely, 2^9712821 is an apocalyptic number.

It is an amenable number.

9712821 is a deficient number, since it is larger than the sum of its proper divisors (3237611).

9712821 is a wasteful number, since it uses less digits than its factorization.

9712821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3237610.

The product of its digits is 2016, while the sum is 30.

The square root of 9712821 is about 3116.5399082957. The cubic root of 9712821 is about 213.3610443061.

The spelling of 9712821 in words is "nine million, seven hundred twelve thousand, eight hundred twenty-one".