1212120221 has 24 divisors (see below), whose sum is σ = 1370853000. Its totient is φ = 1069915392.

The previous prime is 1212120199. The next prime is 1212120223. The reversal of 1212120221 is 1220212121.

It can be written as a sum of positive squares in 12 ways, for example, as 811680100 + 400440121 = 28490^2 + 20011^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1212120221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1212120196 and 1212120205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212120223) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 533075 + ... + 535343.

It is an arithmetic number, because the mean of its divisors is an integer number (57118875).

Almost surely, 2^1212120221 is an apocalyptic number.

It is an amenable number.

1212120221 is a deficient number, since it is larger than the sum of its proper divisors (158732779).

1212120221 is a wasteful number, since it uses less digits than its factorization.

1212120221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2433 (or 2420 counting only the distinct ones).

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

The square root of 1212120221 is about 34815.5169572419. The cubic root of 1212120221 is about 1066.2242736530.

Adding to 1212120221 its reverse (1220212121), we get a palindrome (2432332342).

The spelling of 1212120221 in words is "one billion, two hundred twelve million, one hundred twenty thousand, two hundred twenty-one".