21301002221 has 4 divisors (see below), whose sum is σ = 21305096700. Its totient is φ = 21296907744.

The previous prime is 21301002139. The next prime is 21301002257. The reversal of 21301002221 is 12220010312.

It is a happy number.

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 12848222500 + 8452779721 = 113350^2 + 91939^2 .

It is a cyclic number.

It is not a de Polignac number, because 21301002221 - 2²⁶ = 21233893357 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21301002196 and 21301002205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21301002271) 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, 2039426 + ... + 2049843.

It is an arithmetic number, because the mean of its divisors is an integer number (5326274175).

Almost surely, 2^21301002221 is an apocalyptic number.

It is an amenable number.

21301002221 is a deficient number, since it is larger than the sum of its proper divisors (4094479).

21301002221 is an equidigital number, since it uses as much as digits as its factorization.

21301002221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4094478.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21301002221 its reverse (12220010312), we get a palindrome (33521012533).

The spelling of 21301002221 in words is "twenty-one billion, three hundred one million, two thousand, two hundred twenty-one".