1221335421 has 8 divisors (see below), whose sum is σ = 1629584640. Its totient is φ = 813654912.

The previous prime is 1221335413. The next prime is 1221335431. The reversal of 1221335421 is 1245331221.

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

It is not a de Polignac number, because 1221335421 - 2³ = 1221335413 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1221335391 and 1221335400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221335411) 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, 137140 + ... + 145773.

It is an arithmetic number, because the mean of its divisors is an integer number (203698080).

Almost surely, 2^1221335421 is an apocalyptic number.

It is an amenable number.

1221335421 is a deficient number, since it is larger than the sum of its proper divisors (408249219).

1221335421 is a wasteful number, since it uses less digits than its factorization.

1221335421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284355.

The product of its digits is 1440, while the sum is 24.

The square root of 1221335421 is about 34947.6096607479. The cubic root of 1221335421 is about 1068.9194614909.

Adding to 1221335421 its reverse (1245331221), we get a palindrome (2466666642).

The spelling of 1221335421 in words is "one billion, two hundred twenty-one million, three hundred thirty-five thousand, four hundred twenty-one".