1221306421 has 8 divisors (see below), whose sum is σ = 1247831424. Its totient is φ = 1194804000.

The previous prime is 1221306407. The next prime is 1221306433. The reversal of 1221306421 is 1246031221.

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

It is a cyclic number.

It is not a de Polignac number, because 1221306421 - 2⁷ = 1221306293 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221306392 and 1221306401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221306461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 148801 + ... + 156793.

It is an arithmetic number, because the mean of its divisors is an integer number (155978928).

Almost surely, 2^1221306421 is an apocalyptic number.

It is an amenable number.

1221306421 is a deficient number, since it is larger than the sum of its proper divisors (26525003).

1221306421 is an equidigital number, since it uses as much as digits as its factorization.

1221306421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11291.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 1221306421 is about 34947.1947515105. The cubic root of 1221306421 is about 1068.9110011043.

Adding to 1221306421 its reverse (1246031221), we get a palindrome (2467337642).

The spelling of 1221306421 in words is "one billion, two hundred twenty-one million, three hundred six thousand, four hundred twenty-one".