2638921 has 4 divisors (see below), whose sum is σ = 2682244. Its totient is φ = 2595600.

The previous prime is 2638919. The next prime is 2638931. The reversal of 2638921 is 1298362.

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 622521 + 2016400 = 789^2 + 1420^2 .

It is a cyclic number.

It is not a de Polignac number, because 2638921 - 2¹ = 2638919 is a prime.

It is a d-powerful number, because it can be written as 2¹¹ + 6 + 3¹² + 8⁷ + 9² + 2¹³ + 1 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2638901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21570 + ... + 21691.

It is an arithmetic number, because the mean of its divisors is an integer number (670561).

2^2638921 is an apocalyptic number.

It is an amenable number.

2638921 is a deficient number, since it is larger than the sum of its proper divisors (43323).

2638921 is an equidigital number, since it uses as much as digits as its factorization.

2638921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43322.

The product of its digits is 5184, while the sum is 31.

The square root of 2638921 is about 1624.4756076962. The cubic root of 2638921 is about 138.1896328762.

The spelling of 2638921 in words is "two million, six hundred thirty-eight thousand, nine hundred twenty-one".