10001221021 has 4 divisors (see below), whose sum is σ = 10910422944. Its totient is φ = 9092019100.

The previous prime is 10001221019. The next prime is 10001221081. The reversal of 10001221021 is 12012210001.

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 not a de Polignac number, because 10001221021 - 2¹ = 10001221019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 10001220989 and 10001221007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10001221001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 454600945 + ... + 454600966.

It is an arithmetic number, because the mean of its divisors is an integer number (2727605736).

Almost surely, 2^10001221021 is an apocalyptic number.

10001221021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

10001221021 is a deficient number, since it is larger than the sum of its proper divisors (909201923).

10001221021 is an equidigital number, since it uses as much as digits as its factorization.

10001221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909201922.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 10001221021 its reverse (12012210001), we get a palindrome (22013431022).

The spelling of 10001221021 in words is "ten billion, one million, two hundred twenty-one thousand, twenty-one".