6719991 has 4 divisors (see below), whose sum is σ = 8959992. Its totient is φ = 4479992.

The previous prime is 6719989. The next prime is 6720011. The reversal of 6719991 is 1999176.

6719991 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 6719991 - 2¹ = 6719989 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6719491) 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, 1119996 + ... + 1120001.

It is an arithmetic number, because the mean of its divisors is an integer number (2239998).

Almost surely, 2^6719991 is an apocalyptic number.

6719991 is a deficient number, since it is larger than the sum of its proper divisors (2240001).

6719991 is a wasteful number, since it uses less digits than its factorization.

6719991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2240000.

The product of its digits is 30618, while the sum is 42.

The square root of 6719991 is about 2592.2945434499. The cubic root of 6719991 is about 188.7076749681.

The spelling of 6719991 in words is "six million, seven hundred nineteen thousand, nine hundred ninety-one".