22001021 has 4 divisors (see below), whose sum is σ = 25144032. Its totient is φ = 18858012.

The previous prime is 22000963. The next prime is 22001033. The reversal of 22001021 is 12010022.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12010022 = 2 ⋅6005011.

It is a cyclic number.

It is not a de Polignac number, because 22001021 - 2¹⁸ = 21738877 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 (22001071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1571495 + ... + 1571508.

It is an arithmetic number, because the mean of its divisors is an integer number (6286008).

Almost surely, 2^22001021 is an apocalyptic number.

It is an amenable number.

22001021 is a deficient number, since it is larger than the sum of its proper divisors (3143011).

22001021 is an equidigital number, since it uses as much as digits as its factorization.

22001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3143010.

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

The square root of 22001021 is about 4690.5245975264. The cubic root of 22001021 is about 280.2082676684.

Adding to 22001021 its reverse (12010022), we get a palindrome (34011043).

Subtracting from 22001021 its reverse (12010022), we obtain a palindrome (9990999).

The spelling of 22001021 in words is "twenty-two million, one thousand, twenty-one".