3928521 has 8 divisors (see below), whose sum is σ = 5249664. Its totient is φ = 2613200.

The previous prime is 3928493. The next prime is 3928553. The reversal of 3928521 is 1258293.

It is a happy number.

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 3928521 - 2²¹ = 1831369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3928621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 496 + ... + 2846.

It is an arithmetic number, because the mean of its divisors is an integer number (656208).

Almost surely, 2^3928521 is an apocalyptic number.

It is an amenable number.

3928521 is a deficient number, since it is larger than the sum of its proper divisors (1321143).

3928521 is a wasteful number, since it uses less digits than its factorization.

3928521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2911.

The product of its digits is 4320, while the sum is 30.

The square root of 3928521 is about 1982.0496966524. The cubic root of 3928521 is about 157.7888677026.

Subtracting from 3928521 its product of digits (4320), we obtain a triangular number (3924201 = T₂₈₀₁).

The spelling of 3928521 in words is "three million, nine hundred twenty-eight thousand, five hundred twenty-one".