6633991 has 8 divisors (see below), whose sum is σ = 8165024. Its totient is φ = 5248800.

The previous prime is 6633967. The next prime is 6634009. The reversal of 6633991 is 1993366.

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

It is a 5-Lehmer number, since φ(6633991) divides (6633991-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 6633991 - 2⁹ = 6633479 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6633991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6633931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36360 + ... + 36541.

It is an arithmetic number, because the mean of its divisors is an integer number (1020628).

Almost surely, 2^6633991 is an apocalyptic number.

6633991 is a deficient number, since it is larger than the sum of its proper divisors (1531033).

6633991 is a wasteful number, since it uses less digits than its factorization.

6633991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72921.

The product of its digits is 26244, while the sum is 37.

The square root of 6633991 is about 2575.6535093059. The cubic root of 6633991 is about 187.8992122361.

It can be divided in two parts, 66339 and 91, that multiplied together give a square (6036849 = 2457²).

The spelling of 6633991 in words is "six million, six hundred thirty-three thousand, nine hundred ninety-one".