1213001221 has 4 divisors (see below), whose sum is σ = 1284354252. Its totient is φ = 1141648192.

The previous prime is 1213001191. The next prime is 1213001267. The reversal of 1213001221 is 1221003121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 752898721 + 460102500 = 27439^2 + 21450^2 .

It is not a de Polignac number, because 1213001221 - 2¹³ = 1212993029 is a prime.

It is a Duffinian number.

1213001221 is a modest number, since divided by 1221 gives 1213 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213001281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35676490 + ... + 35676523.

It is an arithmetic number, because the mean of its divisors is an integer number (321088563).

Almost surely, 2^1213001221 is an apocalyptic number.

It is an amenable number.

1213001221 is a deficient number, since it is larger than the sum of its proper divisors (71353031).

1213001221 is an equidigital number, since it uses as much as digits as its factorization.

1213001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71353030.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1213001221 is about 34828.1670634560. The cubic root of 1213001221 is about 1066.4825307909.

Adding to 1213001221 its reverse (1221003121), we get a palindrome (2434004342).

The spelling of 1213001221 in words is "one billion, two hundred thirteen million, one thousand, two hundred twenty-one".