1212101221 has 4 divisors (see below), whose sum is σ = 1230192352. Its totient is φ = 1194010092.

The previous prime is 1212101201. The next prime is 1212101237. The reversal of 1212101221 is 1221012121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1212101221 - 2²¹ = 1210004069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212101201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9045465 + ... + 9045598.

It is an arithmetic number, because the mean of its divisors is an integer number (307548088).

Almost surely, 2^1212101221 is an apocalyptic number.

It is an amenable number.

1212101221 is a deficient number, since it is larger than the sum of its proper divisors (18091131).

1212101221 is an equidigital number, since it uses as much as digits as its factorization.

1212101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18091130.

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

The square root of 1212101221 is about 34815.2440893353. The cubic root of 1212101221 is about 1066.2187025975.

Adding to 1212101221 its reverse (1221012121), we get a palindrome (2433113342).

It can be divided in two parts, 121210 and 1221, that multiplied together give a triangular number (147997410 = T₁₇₂₀₄).

The spelling of 1212101221 in words is "one billion, two hundred twelve million, one hundred one thousand, two hundred twenty-one".