3640421 has 4 divisors (see below), whose sum is σ = 3645600. Its totient is φ = 3635244.

The previous prime is 3640409. The next prime is 3640447. The reversal of 3640421 is 1240463.

It is a happy number.

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: 1240463 = 7 ⋅177209.

It is a cyclic number.

It is not a de Polignac number, because 3640421 - 2¹⁰ = 3639397 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3640393 and 3640402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3640451) 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, 1331 + ... + 3008.

It is an arithmetic number, because the mean of its divisors is an integer number (911400).

Almost surely, 2^3640421 is an apocalyptic number.

It is an amenable number.

3640421 is a deficient number, since it is larger than the sum of its proper divisors (5179).

3640421 is an equidigital number, since it uses as much as digits as its factorization.

3640421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5178.

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 3640421 is about 1907.9887316229. The cubic root of 3640421 is about 153.8333639175.

Adding to 3640421 its reverse (1240463), we get a palindrome (4880884).

The spelling of 3640421 in words is "three million, six hundred forty thousand, four hundred twenty-one".