21121212100210 has 16 divisors (see below), whose sum is σ = 38445352363800. Its totient is φ = 8353558043776.

The previous prime is 21121212100207. The next prime is 21121212100217. The reversal of 21121212100210 is 1200121212112.

It can be written as a sum of positive squares in 4 ways, for example, as 14258923657801 + 6862288442409 = 3776099^2 + 2619597^2 .

It is a super-2 number, since 2×21121212100210² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121212100217) 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, 11865848605 + ... + 11865850384.

Almost surely, 2^{21121212100210} is an apocalyptic number.

21121212100210 is a deficient number, since it is larger than the sum of its proper divisors (17324140263590).

21121212100210 is a wasteful number, since it uses less digits than its factorization.

21121212100210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23731699085.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21121212100210 its reverse (1200121212112), we get a palindrome (22321333312322).

The spelling of 21121212100210 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twelve million, one hundred thousand, two hundred ten".