1243621 has 4 divisors (see below), whose sum is σ = 1246752. Its totient is φ = 1240492.

The previous prime is 1243609. The next prime is 1243631. The reversal of 1243621 is 1263421.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1263421 = 421 ⋅3001.

It is a cyclic number.

It is not a de Polignac number, because 1243621 - 2¹¹ = 1241573 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 (1243631) 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, 865 + ... + 1798.

It is an arithmetic number, because the mean of its divisors is an integer number (311688).

2^1243621 is an apocalyptic number.

It is an amenable number.

1243621 is a deficient number, since it is larger than the sum of its proper divisors (3131).

1243621 is an equidigital number, since it uses as much as digits as its factorization.

1243621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3130.

The product of its digits is 288, while the sum is 19.

The square root of 1243621 is about 1115.1775643367. The cubic root of 1243621 is about 107.5381800564.

It can be divided in two parts, 1243 and 621, that multiplied together give a triangular number (771903 = T₁₂₄₂).

The spelling of 1243621 in words is "one million, two hundred forty-three thousand, six hundred twenty-one".