21020101221 has 8 divisors (see below), whose sum is σ = 32030630464. Its totient is φ = 12011486400.

The previous prime is 21020101213. The next prime is 21020101247. The reversal of 21020101221 is 12210102012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21020101221 - 2³ = 21020101213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21020101197 and 21020101206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020101321) 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 7 ways as a sum of consecutive naturals, for example, 500478580 + ... + 500478621.

It is an arithmetic number, because the mean of its divisors is an integer number (4003828808).

Almost surely, 2^21020101221 is an apocalyptic number.

21020101221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21020101221 is a deficient number, since it is larger than the sum of its proper divisors (11010529243).

21020101221 is a wasteful number, since it uses less digits than its factorization.

21020101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1000957211.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21020101221 its reverse (12210102012), we get a palindrome (33230203233).

The spelling of 21020101221 in words is "twenty-one billion, twenty million, one hundred one thousand, two hundred twenty-one".