668537491111 has 4 divisors (see below), whose sum is σ = 764042846992. Its totient is φ = 573032135232.

The previous prime is 668537491031. The next prime is 668537491129. The reversal of 668537491111 is 111194735866.

It is a happy number.

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 668537491111 - 2¹³ = 668537482919 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 (668537492111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47752677930 + ... + 47752677943.

It is an arithmetic number, because the mean of its divisors is an integer number (191010711748).

Almost surely, 2^668537491111 is an apocalyptic number.

668537491111 is a deficient number, since it is larger than the sum of its proper divisors (95505355881).

668537491111 is an equidigital number, since it uses as much as digits as its factorization.

668537491111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95505355880.

The product of its digits is 1088640, while the sum is 52.

The spelling of 668537491111 in words is "six hundred sixty-eight billion, five hundred thirty-seven million, four hundred ninety-one thousand, one hundred eleven".