1623221 has 4 divisors (see below), whose sum is σ = 1635744. Its totient is φ = 1610700.

The previous prime is 1623203. The next prime is 1623229. The reversal of 1623221 is 1223261.

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 1623221 - 2⁶ = 1623157 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1623221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1623229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6065 + ... + 6326.

It is an arithmetic number, because the mean of its divisors is an integer number (408936).

2^1623221 is an apocalyptic number.

It is an amenable number.

1623221 is a deficient number, since it is larger than the sum of its proper divisors (12523).

1623221 is a wasteful number, since it uses less digits than its factorization.

1623221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12522.

The product of its digits is 144, while the sum is 17.

The square root of 1623221 is about 1274.0569061074. The cubic root of 1623221 is about 117.5238159058.

Adding to 1623221 its reverse (1223261), we get a palindrome (2846482).

The spelling of 1623221 in words is "one million, six hundred twenty-three thousand, two hundred twenty-one".