221421421 has 8 divisors (see below), whose sum is σ = 251004320. Its totient is φ = 193631472.

The previous prime is 221421419. The next prime is 221421461. The reversal of 221421421 is 124124122.

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 221421421 - 2¹ = 221421419 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221421461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 447975 + ... + 448468.

It is an arithmetic number, because the mean of its divisors is an integer number (31375540).

Almost surely, 2^221421421 is an apocalyptic number.

It is an amenable number.

221421421 is a deficient number, since it is larger than the sum of its proper divisors (29582899).

221421421 is a wasteful number, since it uses less digits than its factorization.

221421421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 896475.

The product of its digits is 256, while the sum is 19.

The square root of 221421421 is about 14880.2359188287. The cubic root of 221421421 is about 604.9784123618.

Adding to 221421421 its reverse (124124122), we get a palindrome (345545543).

The spelling of 221421421 in words is "two hundred twenty-one million, four hundred twenty-one thousand, four hundred twenty-one".