6691205162891 has 4 divisors (see below), whose sum is σ = 6691221213792. Its totient is φ = 6691189111992.

The previous prime is 6691205162879. The next prime is 6691205162903. The reversal of 6691205162891 is 1982615021966.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (6691205162879) and next prime (6691205162903).

It is a cyclic number.

It is not a de Polignac number, because 6691205162891 - 2¹⁸ = 6691204900747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6691205162491) 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, 7382996 + ... + 8239601.

It is an arithmetic number, because the mean of its divisors is an integer number (1672805303448).

Almost surely, 2^{6691205162891} is an apocalyptic number.

6691205162891 is a deficient number, since it is larger than the sum of its proper divisors (16050901).

6691205162891 is a wasteful number, since it uses less digits than its factorization.

6691205162891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16050900.

The product of its (nonzero) digits is 2799360, while the sum is 56.

The spelling of 6691205162891 in words is "six trillion, six hundred ninety-one billion, two hundred five million, one hundred sixty-two thousand, eight hundred ninety-one".