21210100210 has 64 divisors (see below), whose sum is σ = 43712379648.
Its totient is φ = 7349531904.
The previous prime is 21210100207. The next prime is 21210100229. The reversal of 21210100210 is 1200101212.
It is a Harshad number since it is a multiple of its sum of digits (10).
It is an unprimeable number.
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 31 ways as a sum of consecutive naturals, for example, 91549 + ... + 225391.
It is an arithmetic number, because the mean of its divisors is an integer number (683005932).
Almost surely, 221210100210 is an apocalyptic number.
21210100210 is an abundant number, since it is smaller than the sum of its proper divisors (22502279438).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21210100210 is a wasteful number, since it uses less digits than its factorization.
21210100210 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 133939.
The product of its (nonzero) digits is 8, while the sum is 10.
Adding to 21210100210 its reverse (1200101212), we get a palindrome (22410201422).
The spelling of 21210100210 in words is "twenty-one billion, two hundred ten million, one hundred thousand, two hundred ten".