6858199991 has 4 divisors (see below), whose sum is σ = 6862464000. Its totient is φ = 6853935984.

The previous prime is 6858199987. The next prime is 6858200017. The reversal of 6858199991 is 1999918586.

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 6858199991 - 2² = 6858199987 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 (6858199921) 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, 2129591 + ... + 2132808.

It is an arithmetic number, because the mean of its divisors is an integer number (1715616000).

Almost surely, 2^6858199991 is an apocalyptic number.

6858199991 is a deficient number, since it is larger than the sum of its proper divisors (4264009).

6858199991 is a wasteful number, since it uses less digits than its factorization.

6858199991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4264008.

The product of its digits is 12597120, while the sum is 65.

The square root of 6858199991 is about 82814.2499271714. The cubic root of 6858199991 is about 1899.9261274141.

The spelling of 6858199991 in words is "six billion, eight hundred fifty-eight million, one hundred ninety-nine thousand, nine hundred ninety-one".