21745108766 has 4 divisors (see below), whose sum is σ = 32617663152. Its totient is φ = 10872554382.

The previous prime is 21745108741. The next prime is 21745108789. The reversal of 21745108766 is 66780154712.

21745108766 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21745108766.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5436277190 + ... + 5436277193.

It is an arithmetic number, because the mean of its divisors is an integer number (8154415788).

Almost surely, 2^21745108766 is an apocalyptic number.

21745108766 is a deficient number, since it is larger than the sum of its proper divisors (10872554386).

21745108766 is a wasteful number, since it uses less digits than its factorization.

21745108766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10872554385.

The product of its (nonzero) digits is 564480, while the sum is 47.

The spelling of 21745108766 in words is "twenty-one billion, seven hundred forty-five million, one hundred eight thousand, seven hundred sixty-six".