10219721 has 4 divisors (see below), whose sum is σ = 10235844. Its totient is φ = 10203600.

The previous prime is 10219709. The next prime is 10219747. The reversal of 10219721 is 12791201.

10219721 = 2260² + 2261².

10219721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5107600 + 5112121 = 2260^2 + 2261^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-10219721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (10219621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7070 + ... + 8391.

It is an arithmetic number, because the mean of its divisors is an integer number (2558961).

Almost surely, 2^10219721 is an apocalyptic number.

10219721 is the 2261-st centered square number.

It is an amenable number.

10219721 is a deficient number, since it is larger than the sum of its proper divisors (16123).

10219721 is an equidigital number, since it uses as much as digits as its factorization.

10219721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16122.

The product of its (nonzero) digits is 252, while the sum is 23.

The square root of 10219721 is about 3196.8298359469. The cubic root of 10219721 is about 217.0099664843.

The spelling of 10219721 in words is "ten million, two hundred nineteen thousand, seven hundred twenty-one".