21718167673 has 4 divisors (see below), whose sum is σ = 21802674420. Its totient is φ = 21633660928.

The previous prime is 21718167661. The next prime is 21718167707. The reversal of 21718167673 is 37676181712.

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

It can be written as a sum of positive squares in 2 ways, for example, as 17395499664 + 4322668009 = 131892^2 + 65747^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21718167673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21718167613) 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, 42252988 + ... + 42253501.

It is an arithmetic number, because the mean of its divisors is an integer number (5450668605).

Almost surely, 2^21718167673 is an apocalyptic number.

It is an amenable number.

21718167673 is a deficient number, since it is larger than the sum of its proper divisors (84506747).

21718167673 is an equidigital number, since it uses as much as digits as its factorization.

21718167673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84506746.

The product of its digits is 592704, while the sum is 49.

The spelling of 21718167673 in words is "twenty-one billion, seven hundred eighteen million, one hundred sixty-seven thousand, six hundred seventy-three".