1212210221 has 4 divisors (see below), whose sum is σ = 1214640000. Its totient is φ = 1209780444.

The previous prime is 1212210173. The next prime is 1212210247. The reversal of 1212210221 is 1220122121.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1220122121 = 277 ⋅4404773.

It is a cyclic number.

It is not a de Polignac number, because 1212210221 - 2²² = 1208015917 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1212210196 and 1212210205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212210821) 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, 1214141 + ... + 1215138.

It is an arithmetic number, because the mean of its divisors is an integer number (303660000).

Almost surely, 2^1212210221 is an apocalyptic number.

It is an amenable number.

1212210221 is a deficient number, since it is larger than the sum of its proper divisors (2429779).

1212210221 is an equidigital number, since it uses as much as digits as its factorization.

1212210221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2429778.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 1212210221 is about 34816.8094603742. The cubic root of 1212210221 is about 1066.2506620722.

Adding to 1212210221 its reverse (1220122121), we get a palindrome (2432332342).

The spelling of 1212210221 in words is "one billion, two hundred twelve million, two hundred ten thousand, two hundred twenty-one".