21766716767 has 4 divisors (see below), whose sum is σ = 21808496016. Its totient is φ = 21724937520.

The previous prime is 21766716761. The next prime is 21766716781. The reversal of 21766716767 is 76761766712.

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 21766716767 - 2¹⁰ = 21766715743 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 (21766716761) 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, 20888843 + ... + 20889884.

It is an arithmetic number, because the mean of its divisors is an integer number (5452124004).

Almost surely, 2^21766716767 is an apocalyptic number.

21766716767 is a deficient number, since it is larger than the sum of its proper divisors (41779249).

21766716767 is an equidigital number, since it uses as much as digits as its factorization.

21766716767 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41779248.

The product of its digits is 6223392, while the sum is 56.

The spelling of 21766716767 in words is "twenty-one billion, seven hundred sixty-six million, seven hundred sixteen thousand, seven hundred sixty-seven".