21723654166771 has 4 divisors (see below), whose sum is σ = 21723700151944. Its totient is φ = 21723608181600.

The previous prime is 21723654166733. The next prime is 21723654166801. The reversal of 21723654166771 is 17766145632712.

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-21723654166771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21723654160771) 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, 22276545 + ... + 23231266.

It is an arithmetic number, because the mean of its divisors is an integer number (5430925037986).

Almost surely, 2^{21723654166771} is an apocalyptic number.

21723654166771 is a deficient number, since it is larger than the sum of its proper divisors (45985173).

21723654166771 is an equidigital number, since it uses as much as digits as its factorization.

21723654166771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45985172.

The product of its digits is 17781120, while the sum is 58.

The spelling of 21723654166771 in words is "twenty-one trillion, seven hundred twenty-three billion, six hundred fifty-four million, one hundred sixty-six thousand, seven hundred seventy-one".