1221440421 has 8 divisors (see below), whose sum is σ = 1629917280. Its totient is φ = 813628592.

The previous prime is 1221440383. The next prime is 1221440431. The reversal of 1221440421 is 1240441221.

1221440421 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

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 1221440421 - 2¹⁰ = 1221439397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221440431) 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, 161955 + ... + 169328.

It is an arithmetic number, because the mean of its divisors is an integer number (203739660).

Almost surely, 2^1221440421 is an apocalyptic number.

It is an amenable number.

1221440421 is a deficient number, since it is larger than the sum of its proper divisors (408476859).

1221440421 is a wasteful number, since it uses less digits than its factorization.

1221440421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332515.

The product of its (nonzero) digits is 512, while the sum is 21.

The square root of 1221440421 is about 34949.1118771279. Note that the first 3 decimals coincide. The cubic root of 1221440421 is about 1068.9500928052.

Adding to 1221440421 its reverse (1240441221), we get a palindrome (2461881642).

The spelling of 1221440421 in words is "one billion, two hundred twenty-one million, four hundred forty thousand, four hundred twenty-one".