1221503121 has 6 divisors (see below), whose sum is σ = 1764393410. Its totient is φ = 814335408.

The previous prime is 1221503111. The next prime is 1221503123. The reversal of 1221503121 is 1213051221.

It can be written as a sum of positive squares in only one way, i.e., 1089000000 + 132503121 = 33000^2 + 11511^2 .

It is not a de Polignac number, because 1221503121 - 2¹⁷ = 1221372049 is a prime.

It is a super-2 number, since 2×1221503121² = 2984139749225481282, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221503094 and 1221503103.

It is not an unprimeable number, because it can be changed into a prime (1221503123) 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 5 ways as a sum of consecutive naturals, for example, 67861276 + ... + 67861293.

Almost surely, 2^1221503121 is an apocalyptic number.

It is an amenable number.

1221503121 is a deficient number, since it is larger than the sum of its proper divisors (542890289).

1221503121 is a wasteful number, since it uses less digits than its factorization.

1221503121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135722575 (or 135722572 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 1221503121 is about 34950.0088841190. The cubic root of 1221503121 is about 1068.9683832386.

Adding to 1221503121 its reverse (1213051221), we get a palindrome (2434554342).

The spelling of 1221503121 in words is "one billion, two hundred twenty-one million, five hundred three thousand, one hundred twenty-one".