4551991 has 4 divisors (see below), whose sum is σ = 4562800. Its totient is φ = 4541184.

The previous prime is 4551983. The next prime is 4552019. The reversal of 4551991 is 1991554.

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 4551991 - 2³ = 4551983 is a prime.

It is a Duffinian number.

4551991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4551091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4746 + ... + 5623.

It is an arithmetic number, because the mean of its divisors is an integer number (1140700).

Almost surely, 2^4551991 is an apocalyptic number.

4551991 is a deficient number, since it is larger than the sum of its proper divisors (10809).

4551991 is a wasteful number, since it uses less digits than its factorization.

4551991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10808.

The product of its digits is 8100, while the sum is 34.

The square root of 4551991 is about 2133.5395473251. The cubic root of 4551991 is about 165.7297460591.

The spelling of 4551991 in words is "four million, five hundred fifty-one thousand, nine hundred ninety-one".