21212112210 has 32 divisors (see below), whose sum is σ = 52284992832. Its totient is φ = 5503682880.

The previous prime is 21212112209. The next prime is 21212112401. The reversal of 21212112210 is 1221121212.

It is a super-4 number, since 4×21212112210⁴ (a number of 42 digits) contains 4444 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21212112210.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9553896 + ... + 9556115.

It is an arithmetic number, because the mean of its divisors is an integer number (1633906026).

Almost surely, 2^21212112210 is an apocalyptic number.

21212112210 is an abundant number, since it is smaller than the sum of its proper divisors (31072880622).

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

21212112210 is a wasteful number, since it uses less digits than its factorization.

21212112210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19110058.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21212112210 its reverse (1221121212), we get a palindrome (22433233422).

The spelling of 21212112210 in words is "twenty-one billion, two hundred twelve million, one hundred twelve thousand, two hundred ten".