21221012210 has 16 divisors (see below), whose sum is σ = 38225506392. Its totient is φ = 8482252800.

The previous prime is 21221012209. The next prime is 21221012213. The reversal of 21221012210 is 1221012212.

It can be written as a sum of positive squares in 4 ways, for example, as 18940090129 + 2280922081 = 137623^2 + 47759^2 .

It is not an unprimeable number, because it can be changed into a prime (21221012213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 754511 + ... + 782130.

Almost surely, 2^21221012210 is an apocalyptic number.

21221012210 is a deficient number, since it is larger than the sum of its proper divisors (17004494182).

21221012210 is a wasteful number, since it uses less digits than its factorization.

21221012210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1538029.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21221012210 its reverse (1221012212), we get a palindrome (22442024422).

The spelling of 21221012210 in words is "twenty-one billion, two hundred twenty-one million, twelve thousand, two hundred ten".