1221043213 has 8 divisors (see below), whose sum is σ = 1317500856. Its totient is φ = 1124947200.

The previous prime is 1221043193. The next prime is 1221043217. The reversal of 1221043213 is 3123401221.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 92217609 + 1128825604 = 9603^2 + 33598^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221043213 - 2¹³ = 1221035021 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 (1221043217) 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 7 ways as a sum of consecutive naturals, for example, 83368 + ... + 96913.

It is an arithmetic number, because the mean of its divisors is an integer number (164687607).

Almost surely, 2^1221043213 is an apocalyptic number.

1221043213 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1221043213 is a deficient number, since it is larger than the sum of its proper divisors (96457643).

1221043213 is a wasteful number, since it uses less digits than its factorization.

1221043213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180815.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 1221043213 is about 34943.4287527712. The cubic root of 1221043213 is about 1068.8342073432.

Adding to 1221043213 its reverse (3123401221), we get a palindrome (4344444434).

The spelling of 1221043213 in words is "one billion, two hundred twenty-one million, forty-three thousand, two hundred thirteen".