1221403221 has 6 divisors (see below), whose sum is σ = 1764249110. Its totient is φ = 814268808.

The previous prime is 1221403153. The next prime is 1221403229. The reversal of 1221403221 is 1223041221.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1126340721 + 95062500 = 33561^2 + 9750^2 .

It is not a de Polignac number, because 1221403221 - 2¹⁵ = 1221370453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221403194 and 1221403203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221403229) 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, 67855726 + ... + 67855743.

Almost surely, 2^1221403221 is an apocalyptic number.

It is an amenable number.

1221403221 is a deficient number, since it is larger than the sum of its proper divisors (542845889).

1221403221 is a wasteful number, since it uses less digits than its factorization.

1221403221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135711475 (or 135711472 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1221403221 is about 34948.5796707105. The cubic root of 1221403221 is about 1068.9392407689.

Adding to 1221403221 its reverse (1223041221), we get a palindrome (2444444442).

It can be divided in two parts, 12 and 21403221, that multiplied together give a palindrome (256838652).

The spelling of 1221403221 in words is "one billion, two hundred twenty-one million, four hundred three thousand, two hundred twenty-one".