621221 has 4 divisors (see below), whose sum is σ = 635712. Its totient is φ = 606732.

The previous prime is 621217. The next prime is 621223. The reversal of 621221 is 122126.

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 a cyclic number.

It is not a de Polignac number, because 621221 - 2² = 621217 is a prime.

It is a plaindrome in base 14.

It is a junction number, because it is equal to n+sod(n) for n = 621196 and 621205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621223) 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, 7181 + ... + 7266.

It is an arithmetic number, because the mean of its divisors is an integer number (158928).

2⁶²¹²²¹ is an apocalyptic number.

It is an amenable number.

621221 is a deficient number, since it is larger than the sum of its proper divisors (14491).

621221 is a wasteful number, since it uses less digits than its factorization.

621221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14490.

The product of its digits is 48, while the sum is 14.

The square root of 621221 is about 788.1757418241. The cubic root of 621221 is about 85.3261288812.

Adding to 621221 its reverse (122126), we get a palindrome (743347).

The spelling of 621221 in words is "six hundred twenty-one thousand, two hundred twenty-one".