3928921 has 8 divisors (see below), whose sum is σ = 4181760. Its totient is φ = 3678528.

The previous prime is 3928913. The next prime is 3928931. The reversal of 3928921 is 1298293.

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

It is not a de Polignac number, because 3928921 - 2³ = 3928913 is a prime.

It is an Ulam number.

It is a Duffinian number.

3928921 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3928931) 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, 3580 + ... + 4546.

It is an arithmetic number, because the mean of its divisors is an integer number (522720).

Almost surely, 2^3928921 is an apocalyptic number.

It is an amenable number.

3928921 is a deficient number, since it is larger than the sum of its proper divisors (252839).

3928921 is a wasteful number, since it uses less digits than its factorization.

3928921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1223.

The product of its digits is 7776, while the sum is 34.

The square root of 3928921 is about 1982.1505997275. The cubic root of 3928921 is about 157.7942228482.

The spelling of 3928921 in words is "three million, nine hundred twenty-eight thousand, nine hundred twenty-one".