21221220010 has 16 divisors (see below), whose sum is σ = 38281788936. Its totient is φ = 8469911808.

The previous prime is 21221219983. The next prime is 21221220011. The reversal of 21221220010 is 1002212212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 20888631841 + 332588169 = 144529^2 + 18237^2 .

It is not an unprimeable number, because it can be changed into a prime (21221220011) 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, 2317227 + ... + 2326366.

Almost surely, 2^21221220010 is an apocalyptic number.

21221220010 is a deficient number, since it is larger than the sum of its proper divisors (17060568926).

21221220010 is a wasteful number, since it uses less digits than its factorization.

21221220010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4644057.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21221220010 its reverse (1002212212), we get a palindrome (22223432222).

The spelling of 21221220010 in words is "twenty-one billion, two hundred twenty-one million, two hundred twenty thousand, ten".