21212221003 has 4 divisors (see below), whose sum is σ = 21212682120. Its totient is φ = 21211759888.

The previous prime is 21212220949. The next prime is 21212221007. The reversal of 21212221003 is 30012221212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21212221003 - 2¹³ = 21212212811 is a prime.

It is a super-2 number, since 2×21212221003² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212221007) 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, 152818 + ... + 256471.

It is an arithmetic number, because the mean of its divisors is an integer number (5303170530).

Almost surely, 2^21212221003 is an apocalyptic number.

21212221003 is a deficient number, since it is larger than the sum of its proper divisors (461117).

21212221003 is an equidigital number, since it uses as much as digits as its factorization.

21212221003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 461116.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21212221003 its reverse (30012221212), we get a palindrome (51224442215).

The spelling of 21212221003 in words is "twenty-one billion, two hundred twelve million, two hundred twenty-one thousand, three".