2123621 has 4 divisors (see below), whose sum is σ = 2145612. Its totient is φ = 2101632.

The previous prime is 2123617. The next prime is 2123663. The reversal of 2123621 is 1263212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1288225 + 835396 = 1135^2 + 914^2 .

It is a cyclic number.

It is not a de Polignac number, because 2123621 - 2² = 2123617 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 2123621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2120621) 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, 10850 + ... + 11043.

It is an arithmetic number, because the mean of its divisors is an integer number (536403).

2^2123621 is an apocalyptic number.

It is an amenable number.

2123621 is a deficient number, since it is larger than the sum of its proper divisors (21991).

2123621 is an equidigital number, since it uses as much as digits as its factorization.

2123621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21990.

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

The square root of 2123621 is about 1457.2649038524. The cubic root of 2123621 is about 128.5362633400.

Adding to 2123621 its reverse (1263212), we get a palindrome (3386833).

It can be divided in two parts, 2123 and 621, that added together give a cube (2744 = 14³).

The spelling of 2123621 in words is "two million, one hundred twenty-three thousand, six hundred twenty-one".