21755705767 has 4 divisors (see below), whose sum is σ = 21756341880. Its totient is φ = 21755069656.

The previous prime is 21755705753. The next prime is 21755705857. The reversal of 21755705767 is 76750755712.

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 21755705767 - 2³¹ = 19608222119 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 (21755705707) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 263653 + ... + 336190.

It is an arithmetic number, because the mean of its divisors is an integer number (5439085470).

Almost surely, 2^21755705767 is an apocalyptic number.

21755705767 is a deficient number, since it is larger than the sum of its proper divisors (636113).

21755705767 is an equidigital number, since it uses as much as digits as its factorization.

21755705767 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636112.

The product of its (nonzero) digits is 3601500, while the sum is 52.

The spelling of 21755705767 in words is "twenty-one billion, seven hundred fifty-five million, seven hundred five thousand, seven hundred sixty-seven".