420001221 has 4 divisors (see below), whose sum is σ = 560001632. Its totient is φ = 280000812.

The previous prime is 420001217. The next prime is 420001223. The reversal of 420001221 is 122100024.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 420001221 - 2² = 420001217 is a prime.

It is a Duffinian number.

420001221 is a modest number, since divided by 1221 gives 420 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 420001197 and 420001206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (420001223) 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 3 ways as a sum of consecutive naturals, for example, 70000201 + ... + 70000206.

It is an arithmetic number, because the mean of its divisors is an integer number (140000408).

Almost surely, 2^420001221 is an apocalyptic number.

It is an amenable number.

420001221 is a deficient number, since it is larger than the sum of its proper divisors (140000411).

420001221 is a wasteful number, since it uses less digits than its factorization.

420001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140000410.

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 420001221 is about 20493.9313212473. The cubic root of 420001221 is about 748.8879644285.

Adding to 420001221 its reverse (122100024), we get a palindrome (542101245).

The spelling of 420001221 in words is "four hundred twenty million, one thousand, two hundred twenty-one".