6309991 has 4 divisors (see below), whose sum is σ = 6417000. Its totient is φ = 6202984.

The previous prime is 6309973. The next prime is 6309997. The reversal of 6309991 is 1999036.

6309991 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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 6309991 - 2⁵ = 6309959 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6309991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6309997) 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, 53416 + ... + 53533.

It is an arithmetic number, because the mean of its divisors is an integer number (1604250).

Almost surely, 2^6309991 is an apocalyptic number.

6309991 is a deficient number, since it is larger than the sum of its proper divisors (107009).

6309991 is a wasteful number, since it uses less digits than its factorization.

6309991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107008.

The product of its (nonzero) digits is 13122, while the sum is 37.

The square root of 6309991 is about 2511.9695459937. The cubic root of 6309991 is about 184.7890558882.

It can be divided in two parts, 63099 and 91, that added together give a triangular number (63190 = T₃₅₅).

The spelling of 6309991 in words is "six million, three hundred nine thousand, nine hundred ninety-one".