1220421 has 4 divisors (see below), whose sum is σ = 1627232. Its totient is φ = 813612.

The previous prime is 1220411. The next prime is 1220423. The reversal of 1220421 is 1240221.

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 1220421 - 2⁹ = 1219909 is a prime.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1220397 and 1220406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203401 + ... + 203406.

It is an arithmetic number, because the mean of its divisors is an integer number (406808).

2^1220421 is an apocalyptic number.

It is an amenable number.

1220421 is a deficient number, since it is larger than the sum of its proper divisors (406811).

1220421 is an equidigital number, since it uses as much as digits as its factorization.

1220421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406810.

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

The square root of 1220421 is about 1104.7266630257. The cubic root of 1220421 is about 106.8652626127.

Adding to 1220421 its reverse (1240221), we get a palindrome (2460642).

The spelling of 1220421 in words is "one million, two hundred twenty thousand, four hundred twenty-one".