21012221210 has 8 divisors (see below), whose sum is σ = 37821998196.
Its totient is φ = 8404888480.
The previous prime is 21012221207. The next prime is 21012221311. The reversal of 21012221210 is 1212221012.
Adding to 21012221210 its reverse (1212221012), we get a palindrome (22224442222).
It can be written as a sum of positive squares in 2 ways, for example, as 18294997081 + 2717224129 = 135259^2 + 52127^2
It is a sphenic number, since it is the product of 3 distinct primes.
It is an unprimeable number.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1050611051 + ... + 1050611070.
Almost surely, 221012221210 is an apocalyptic number.
21012221210 is a deficient number, since it is larger than the sum of its proper divisors (16809776986).
21012221210 is a wasteful number, since it uses less digits than its factorization.
21012221210 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 2101222128.
The product of its (nonzero) digits is 32, while the sum is 14.
The spelling of 21012221210 in words is "twenty-one billion, twelve million, two hundred twenty-one thousand, two hundred ten".