212121210 has 128 divisors (see below), whose sum is σ = 599975424. Its totient is φ = 47001600.

The previous prime is 212121209. The next prime is 212121289. The reversal of 212121210 is 12121212.

212121210 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1548262 + ... + 1548398.

It is an arithmetic number, because the mean of its divisors is an integer number (4687308).

Almost surely, 2^212121210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 212121210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (299987712).

212121210 is an abundant number, since it is smaller than the sum of its proper divisors (387854214).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

212121210 is a wasteful number, since it uses less digits than its factorization.

212121210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 212121210 is about 14564.3815522665. The cubic root of 212121210 is about 596.3868129195.

Adding to 212121210 its reverse (12121212), we get a palindrome (224242422).

It can be divided in two parts, 21212 and 1210, that added together give a palindrome (22422).

The spelling of 212121210 in words is "two hundred twelve million, one hundred twenty-one thousand, two hundred ten".