3638921 has 8 divisors (see below), whose sum is σ = 4275264. Its totient is φ = 3053520.

The previous prime is 3638917. The next prime is 3638923. The reversal of 3638921 is 1298363.

Added to its reverse (1298363) it gives a square (4937284 = 2222²).

3638921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3638921 - 2² = 3638917 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3638923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12581 + ... + 12866.

It is an arithmetic number, because the mean of its divisors is an integer number (534408).

Almost surely, 2^3638921 is an apocalyptic number.

It is an amenable number.

3638921 is a deficient number, since it is larger than the sum of its proper divisors (636343).

3638921 is a wasteful number, since it uses less digits than its factorization.

3638921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25471.

The product of its digits is 7776, while the sum is 32.

The square root of 3638921 is about 1907.5956070404. The cubic root of 3638921 is about 153.8122325020.

Adding to 3638921 its reverse (1298363), we get a square (4937284 = 2222²).

It can be divided in two parts, 363 and 8921, that multiplied together give a palindrome (3238323).

The spelling of 3638921 in words is "three million, six hundred thirty-eight thousand, nine hundred twenty-one".