1221333021 has 6 divisors (see below), whose sum is σ = 1764147710. Its totient is φ = 814222008.

The previous prime is 1221333019. The next prime is 1221333059. The reversal of 1221333021 is 1203331221.

It can be written as a sum of positive squares in only one way, i.e., 751527396 + 469805625 = 27414^2 + 21675^2 .

It is not a de Polignac number, because 1221333021 - 2¹ = 1221333019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221332985 and 1221333003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221333011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 67851826 + ... + 67851843.

Almost surely, 2^1221333021 is an apocalyptic number.

It is an amenable number.

1221333021 is a deficient number, since it is larger than the sum of its proper divisors (542814689).

1221333021 is a wasteful number, since it uses less digits than its factorization.

1221333021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135703675 (or 135703672 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 1221333021 is about 34947.5753236187. The cubic root of 1221333021 is about 1068.9187613261.

Adding to 1221333021 its reverse (1203331221), we get a palindrome (2424664242).

The spelling of 1221333021 in words is "one billion, two hundred twenty-one million, three hundred thirty-three thousand, twenty-one".