211212121 has 2 divisors, whose sum is σ = 211212122. Its totient is φ = 211212120.

The previous prime is 211212101. The next prime is 211212137. The reversal of 211212121 is 121212112.

It is a m-pointer prime, because the next prime (211212137) can be obtained adding 211212121 to its product of digits (16).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138297600 + 72914521 = 11760^2 + 8539^2 .

It is a cyclic number.

It is not a de Polignac number, because 211212121 - 2¹⁷ = 211081049 is a prime.

It is a super-2 number, since 2×211212121² = 89221120114637282, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (211212101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105606060 + 105606061.

It is an arithmetic number, because the mean of its divisors is an integer number (105606061).

Almost surely, 2^211212121 is an apocalyptic number.

It is an amenable number.

211212121 is a deficient number, since it is larger than the sum of its proper divisors (1).

211212121 is an equidigital number, since it uses as much as digits as its factorization.

211212121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16, while the sum is 13.

The square root of 211212121 is about 14533.1387181159. The cubic root of 211212121 is about 595.5336135217.

Adding to 211212121 its reverse (121212112), we get a palindrome (332424233).

Subtracting from 211212121 its reverse (121212112), we obtain a palindrome (90000009).

It can be divided in two parts, 2112 and 12121, that multiplied together give a palindrome (25599552).

The spelling of 211212121 in words is "two hundred eleven million, two hundred twelve thousand, one hundred twenty-one".