1221623 has 4 divisors (see below), whose sum is σ = 1315608. Its totient is φ = 1127640.

The previous prime is 1221601. The next prime is 1221631. The reversal of 1221623 is 3261221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221623 - 2⁶ = 1221559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221653) 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, 46973 + ... + 46998.

It is an arithmetic number, because the mean of its divisors is an integer number (328902).

2^1221623 is an apocalyptic number.

1221623 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1221623 is a deficient number, since it is larger than the sum of its proper divisors (93985).

1221623 is an equidigital number, since it uses as much as digits as its factorization.

1221623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93984.

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

The square root of 1221623 is about 1105.2705551131. The cubic root of 1221623 is about 106.9003351813.

Adding to 1221623 its reverse (3261221), we get a palindrome (4482844).

The spelling of 1221623 in words is "one million, two hundred twenty-one thousand, six hundred twenty-three".