10001021 has 4 divisors (see below), whose sum is σ = 10435872. Its totient is φ = 9566172.

The previous prime is 10001009. The next prime is 10001053. The reversal of 10001021 is 12010001.

It is a happy number.

10001021 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-10001021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 10000996 and 10001014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10001081) 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, 217391 + ... + 217436.

It is an arithmetic number, because the mean of its divisors is an integer number (2608968).

Almost surely, 2^10001021 is an apocalyptic number.

It is an amenable number.

10001021 is a deficient number, since it is larger than the sum of its proper divisors (434851).

10001021 is an equidigital number, since it uses as much as digits as its factorization.

10001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 434850.

The product of its (nonzero) digits is 2, while the sum is 5.

The square root of 10001021 is about 3162.4390903225. The cubic root of 10001021 is about 215.4508010131.

Adding to 10001021 its reverse (12010001), we get a palindrome (22011022).

Multiplying 10001021 by its reverse (12010001), we get a palindrome (120112272211021).

The spelling of 10001021 in words is "ten million, one thousand, twenty-one".