3815421 has 4 divisors (see below), whose sum is σ = 5087232. Its totient is φ = 2543612.

The previous prime is 3815407. The next prime is 3815423. The reversal of 3815421 is 1245183.

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: 1245183 = 3 ⋅415061.

It is a cyclic number.

It is not a de Polignac number, because 3815421 - 2⁵ = 3815389 is a prime.

It is a D-number.

3815421 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 3815391 and 3815400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3815423) 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, 635901 + ... + 635906.

It is an arithmetic number, because the mean of its divisors is an integer number (1271808).

Almost surely, 2^3815421 is an apocalyptic number.

It is an amenable number.

3815421 is a deficient number, since it is larger than the sum of its proper divisors (1271811).

3815421 is a wasteful number, since it uses less digits than its factorization.

3815421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1271810.

The product of its digits is 960, while the sum is 24.

The square root of 3815421 is about 1953.3102672131. The cubic root of 3815421 is about 156.2598807618.

The spelling of 3815421 in words is "three million, eight hundred fifteen thousand, four hundred twenty-one".