81668445223 has 4 divisors (see below), whose sum is σ = 81707097808. Its totient is φ = 81629792640.

The previous prime is 81668445151. The next prime is 81668445263. The reversal of 81668445223 is 32254486618.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81668445223 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 (81668445263) 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, 19323123 + ... + 19327348.

It is an arithmetic number, because the mean of its divisors is an integer number (20426774452).

Almost surely, 2^81668445223 is an apocalyptic number.

81668445223 is a deficient number, since it is larger than the sum of its proper divisors (38652585).

81668445223 is a wasteful number, since it uses less digits than its factorization.

81668445223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38652584.

The product of its digits is 2211840, while the sum is 49.

The spelling of 81668445223 in words is "eighty-one billion, six hundred sixty-eight million, four hundred forty-five thousand, two hundred twenty-three".