3905021 has 4 divisors (see below), whose sum is σ = 3921600. Its totient is φ = 3888444.

The previous prime is 3905003. The next prime is 3905023. The reversal of 3905021 is 1205093.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3905021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 11.

It is a junction number, because it is equal to n+sod(n) for n = 3904984 and 3905002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3905023) 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, 7931 + ... + 8408.

It is an arithmetic number, because the mean of its divisors is an integer number (980400).

Almost surely, 2^3905021 is an apocalyptic number.

It is an amenable number.

3905021 is a deficient number, since it is larger than the sum of its proper divisors (16579).

3905021 is a wasteful number, since it uses less digits than its factorization.

3905021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16578.

The product of its (nonzero) digits is 270, while the sum is 20.

The square root of 3905021 is about 1976.1125980065. The cubic root of 3905021 is about 157.4736127794.

The spelling of 3905021 in words is "three million, nine hundred five thousand, twenty-one".