10021221 has 24 divisors (see below), whose sum is σ = 16777280. Its totient is φ = 5645376.

The previous prime is 10021217. The next prime is 10021237. The reversal of 10021221 is 12212001.

10021221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 10021221 - 2² = 10021217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10021241) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3510 + ... + 5688.

Almost surely, 2^10021221 is an apocalyptic number.

It is an amenable number.

10021221 is a deficient number, since it is larger than the sum of its proper divisors (6756059).

10021221 is a wasteful number, since it uses less digits than its factorization.

10021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2265 (or 2262 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 10021221 is about 3165.6312166770. The cubic root of 10021221 is about 215.5957588577.

Adding to 10021221 its reverse (12212001), we get a palindrome (22233222).

It can be divided in two parts, 100 and 21221, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 10021221 in words is "ten million, twenty-one thousand, two hundred twenty-one".