4023991 has 4 divisors (see below), whose sum is σ = 4235800. Its totient is φ = 3812184.

The previous prime is 4023973. The next prime is 4023997. The reversal of 4023991 is 1993204.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 4023991 - 2⁹ = 4023479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4023997) 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, 105876 + ... + 105913.

It is an arithmetic number, because the mean of its divisors is an integer number (1058950).

Almost surely, 2^4023991 is an apocalyptic number.

4023991 is a deficient number, since it is larger than the sum of its proper divisors (211809).

4023991 is a wasteful number, since it uses less digits than its factorization.

4023991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211808.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 4023991 is about 2005.9887836177. The cubic root of 4023991 is about 159.0568339736.

The spelling of 4023991 in words is "four million, twenty-three thousand, nine hundred ninety-one".