4031921 has 4 divisors (see below), whose sum is σ = 4036452. Its totient is φ = 4027392.

The previous prime is 4031903. The next prime is 4031947. The reversal of 4031921 is 1291304.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 2686321 + 1345600 = 1639^2 + 1160^2 .

It is a cyclic number.

It is not a de Polignac number, because 4031921 - 2¹⁴ = 4015537 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 4031893 and 4031902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4031221) 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, 440 + ... + 2873.

It is an arithmetic number, because the mean of its divisors is an integer number (1009113).

Almost surely, 2^4031921 is an apocalyptic number.

It is an amenable number.

4031921 is a deficient number, since it is larger than the sum of its proper divisors (4531).

4031921 is a wasteful number, since it uses less digits than its factorization.

4031921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4530.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 4031921 is about 2007.9643921146. The cubic root of 4031921 is about 159.1612488067.

The spelling of 4031921 in words is "four million, thirty-one thousand, nine hundred twenty-one".